String.IndexOf Metod

public:
 int IndexOf(System::String ^ value, int startIndex, int count, StringComparison comparisonType);

public int IndexOf(string value, int startIndex, int count, StringComparison comparisonType);

member this.IndexOf : string * int * int * StringComparison -> int

Public Function IndexOf (value As String, startIndex As Integer, count As Integer, comparisonType As StringComparison) As Integer

Parametrar

Returer

Parameterns value nollbaserade indexposition från början av den aktuella instansen om strängen hittas eller -1 om den inte är det. Om value är Emptyär startIndexreturvärdet .

Undantag

Exempel

I följande exempel visas tre överlagringar av IndexOf metoden som hittar den första förekomsten av en sträng i en annan sträng med hjälp av olika värden för StringComparison uppräkningen.

// This code example demonstrates the 
// System.String.IndexOf(String, ..., StringComparison) methods.

using System;
using System.Threading;
using System.Globalization;

class Sample 
{
    public static void Main() 
    {
    string intro = "Find the first occurrence of a character using different " + 
                   "values of StringComparison.";
    string resultFmt = "Comparison: {0,-28} Location: {1,3}";

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
    string CapitalAWithRing = "\u00c5"; 

// Define a string to search. 
// The result of combining the characters LATIN SMALL LETTER A and COMBINING 
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
    string cat = "A Cheshire c" + "\u0061\u030a" + "t";

    int loc = 0;
    StringComparison[] scValues = {
        StringComparison.CurrentCulture,
        StringComparison.CurrentCultureIgnoreCase,
        StringComparison.InvariantCulture,
        StringComparison.InvariantCultureIgnoreCase,
        StringComparison.Ordinal,
        StringComparison.OrdinalIgnoreCase };

// Clear the screen and display an introduction.
    Console.Clear();
    Console.WriteLine(intro);

// Display the current culture because culture affects the result. For example, 
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

    Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
    Console.WriteLine("The current culture is \"{0}\" - {1}.", 
                       Thread.CurrentThread.CurrentCulture.Name,
                       Thread.CurrentThread.CurrentCulture.DisplayName);

// Display the string to search for and the string to search.
    Console.WriteLine("Search for the string \"{0}\" in the string \"{1}\"", 
                       CapitalAWithRing, cat);
    Console.WriteLine();

// Note that in each of the following searches, we look for 
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
// the string was not found.
// Search using different values of StringComparison. Specify the start 
// index and count. 

    Console.WriteLine("Part 1: Start index and count are specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. Specify the 
// start index. 
    Console.WriteLine("\nPart 2: Start index is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. 
    Console.WriteLine("\nPart 3: Neither start index nor count is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }
    }
}

/*
Note: This code example was executed on a console whose user interface 
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*/

// This code example demonstrates the
// System.String.IndexOf(String, ..., StringComparison) methods.

open System
open System.Threading
open System.Globalization

let intro = "Find the first occurrence of a character using different values of StringComparison."

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
let CapitalAWithRing = "\u00c5"

// Define a string to search.
// The result of combining the characters LATIN SMALL LETTER A and COMBINING
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
let cat = "A Cheshire c" + "\u0061\u030a" + "t"

let scValues = 
    [| StringComparison.CurrentCulture
       StringComparison.CurrentCultureIgnoreCase
       StringComparison.InvariantCulture
       StringComparison.InvariantCultureIgnoreCase
       StringComparison.Ordinal
       StringComparison.OrdinalIgnoreCase |]

// Clear the screen and display an introduction.
Console.Clear()
printfn $"{intro}"

// Display the current culture because culture affects the result. For example,
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

Thread.CurrentThread.CurrentCulture <- CultureInfo "en-US"
printfn $"The current culture is \"{Thread.CurrentThread.CurrentCulture.Name}\" - {Thread.CurrentThread.CurrentCulture.DisplayName}."

// Display the string to search for and the string to search.
printfn $"Search for the string \"{CapitalAWithRing}\" in the string \"{cat}\"\n"

// Note that in each of the following searches, we look for
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates
// the string was not found.
// Search using different values of StringComparison. Specify the start
// index and count.

printfn "Part 1: Start index and count are specified."
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
    printfn $"Comparison: {sc,-28} Location: {loc,3}"

// Search using different values of StringComparison. Specify the
// start index.
printfn "\nPart 2: Start index is specified."
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, 0, sc)
    printfn $"Comparison: {sc,-28} Location: {loc,3}"

// Search using different values of StringComparison.
Console.WriteLine("\nPart 3: Neither start index nor count is specified.")
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, sc)
    Console.WriteLine("Comparison: {0,-28} Location: {1,3}", sc, loc)

(*
Note: This code example was executed on a console whose user interface
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*)

' This code example demonstrates the 
' System.String.IndexOf(String, ..., StringComparison) methods.

Imports System.Threading
Imports System.Globalization

Class Sample
    Public Shared Sub Main() 
        Dim intro As String = "Find the first occurrence of a character using different " & _
                              "values of StringComparison."
        Dim resultFmt As String = "Comparison: {0,-28} Location: {1,3}"
        
        ' Define a string to search for.
        ' U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
        Dim CapitalAWithRing As String = "Å"
        
        ' Define a string to search. 
        ' The result of combining the characters LATIN SMALL LETTER A and COMBINING 
        ' RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
        ' LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
        Dim cat As String = "A Cheshire c" & "å" & "t"
        
        Dim loc As Integer = 0
        Dim scValues As StringComparison() =  { _
                        StringComparison.CurrentCulture, _
                        StringComparison.CurrentCultureIgnoreCase, _
                        StringComparison.InvariantCulture, _
                        StringComparison.InvariantCultureIgnoreCase, _
                        StringComparison.Ordinal, _
                        StringComparison.OrdinalIgnoreCase }
        Dim sc As StringComparison
        
        ' Clear the screen and display an introduction.
        Console.Clear()
        Console.WriteLine(intro)
        
        ' Display the current culture because culture affects the result. For example, 
        ' try this code example with the "sv-SE" (Swedish-Sweden) culture.
        Thread.CurrentThread.CurrentCulture = New CultureInfo("en-US")
        Console.WriteLine("The current culture is ""{0}"" - {1}.", _
                           Thread.CurrentThread.CurrentCulture.Name, _ 
                           Thread.CurrentThread.CurrentCulture.DisplayName)
        
        ' Display the string to search for and the string to search.
        Console.WriteLine("Search for the string ""{0}"" in the string ""{1}""", _
                           CapitalAWithRing, cat)
        Console.WriteLine()
        
        ' Note that in each of the following searches, we look for 
        ' LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
        ' LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
        ' the string was not found.
        ' Search using different values of StringComparison. Specify the start 
        ' index and count.

        Console.WriteLine("Part 1: Start index and count are specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. Specify the 
        ' start index. 

        Console.WriteLine(vbCrLf & "Part 2: Start index is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. 

        Console.WriteLine(vbCrLf & "Part 3: Neither start index nor count is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
    
    End Sub
End Class

'
'Note: This code example was executed on a console whose user interface 
'culture is "en-US" (English-United States).
'
'This code example produces the following results:
'
'Find the first occurrence of a character using different values of StringComparison.
'The current culture is "en-US" - English (United States).
'Search for the string "Å" in the string "A Cheshire ca°t"
'
'Part 1: Start index and count are specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 2: Start index is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 3: Neither start index nor count is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'

Kommentarer

Indexnumreringen börjar från 0 (noll). Parametern startIndex kan variera från 0 till längden på stränginstansen.

Sökningen börjar vid startIndex och fortsätter till startIndex + count -1. Tecknet på startIndex + count ingår inte i sökningen.

Parametern comparisonType anger att söka efter parametern value med hjälp av den aktuella eller invarianta kulturen, med hjälp av en skiftlägeskänslig eller skiftlägeskänslig sökning och med hjälp av ord- eller ordningstalsjämförelseregler.

Anteckningar till anropare

Teckenuppsättningar innehåller ignorerbara tecken, som är tecken som inte beaktas när man utför en språklig eller kulturspecifik jämförelse. I en kulturkänslig sökning (dvs. om comparisonType den inte Ordinal är eller OrdinalIgnoreCase), om value den innehåller ett okunnigt tecken, motsvarar resultatet att söka med det tecknet borttaget. Om value endast består av ett eller flera okunniga tecken IndexOf(String, Int32, Int32, StringComparison) returnerar startIndexmetoden alltid , vilket är teckenpositionen där sökningen börjar.

I följande exempel IndexOf(String, Int32, Int32, StringComparison) används metoden för att hitta positionen för ett mjukt bindestreck (U+00AD) följt av ett "m" med början i den tredje till sjätte teckenpositionen i två strängar. Endast en av strängarna innehåller den delsträng som krävs. Om exemplet körs på .NET Framework 4 eller senare, i båda fallen, eftersom det mjuka bindestrecket är ett okunnigt tecken, returnerar metoden indexet "m" i strängen när den utför en kulturkänslig jämförelse. När den utför en ordningsjämförelse hittar den dock endast delsträngen i den första strängen. Observera att när det gäller den första strängen, som innehåller det mjuka bindestrecket följt av ett "m", returnerar metoden inte indexet för det mjuka bindestrecket, utan returnerar i stället indexet för "m" när den utför en kulturkänslig jämförelse. Metoden returnerar indexet för det mjuka bindestrecket i den första strängen endast när den utför en ordningsjämförelse.

using System;

public class Example
{
    public static void Main()
    {

        string searchString = "\u00ADm";
        string s1 = "ani\u00ADmal" ;
        string s2 = "animal";

        Console.WriteLine(s1.IndexOf(searchString, 2, 4, StringComparison.CurrentCulture));
        Console.WriteLine(s1.IndexOf(searchString, 2, 4, StringComparison.Ordinal));
        Console.WriteLine(s2.IndexOf(searchString, 2, 4, StringComparison.CurrentCulture));
        Console.WriteLine(s2.IndexOf(searchString, 2, 4, StringComparison.Ordinal));

        // The example displays the following output:
        //       4
        //       3
        //       3
        //       -1
    }
}

open System

let searchString = "\u00ADm"
let s1 = "ani\u00ADmal"
let s2 = "animal"

printfn $"{s1.IndexOf(searchString, 2, 4, StringComparison.CurrentCulture)}"
printfn $"{s1.IndexOf(searchString, 2, 4, StringComparison.Ordinal)}"
printfn $"{s2.IndexOf(searchString, 2, 4, StringComparison.CurrentCulture)}"
printfn $"{s2.IndexOf(searchString, 2, 4, StringComparison.Ordinal)}"

// The example displays the following output:
//       4
//       3
//       3
//       -1

Module Example
   Public Sub Main()
      Dim searchString As String = Chrw(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"

      Console.WriteLine(s1.IndexOf(searchString, 2, 4, StringComparison.CurrentCulture))
      Console.WriteLine(s1.IndexOf(searchString, 2, 4, StringComparison.Ordinal))
      Console.WriteLine(s2.IndexOf(searchString, 2, 4, StringComparison.CurrentCulture))
      Console.WriteLine(s2.IndexOf(searchString, 2, 4, StringComparison.Ordinal))
   End Sub
End Module
' The example displays the following output:
'       4
'       3
'       3
'       -1

public:
 int IndexOf(System::String ^ value, int startIndex, StringComparison comparisonType);

public int IndexOf(string value, int startIndex, StringComparison comparisonType);

member this.IndexOf : string * int * StringComparison -> int

Public Function IndexOf (value As String, startIndex As Integer, comparisonType As StringComparison) As Integer

Parametrar

Returer

Parameterns value nollbaserade indexposition från början av den aktuella instansen om strängen hittas eller -1 om den inte är det. Om value är Emptyär startIndexreturvärdet .

Undantag

Exempel

I följande exempel visas tre överlagringar av IndexOf metoden som hittar den första förekomsten av en sträng i en annan sträng med hjälp av olika värden för StringComparison uppräkningen.

// This code example demonstrates the 
// System.String.IndexOf(String, ..., StringComparison) methods.

using System;
using System.Threading;
using System.Globalization;

class Sample 
{
    public static void Main() 
    {
    string intro = "Find the first occurrence of a character using different " + 
                   "values of StringComparison.";
    string resultFmt = "Comparison: {0,-28} Location: {1,3}";

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
    string CapitalAWithRing = "\u00c5"; 

// Define a string to search. 
// The result of combining the characters LATIN SMALL LETTER A and COMBINING 
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
    string cat = "A Cheshire c" + "\u0061\u030a" + "t";

    int loc = 0;
    StringComparison[] scValues = {
        StringComparison.CurrentCulture,
        StringComparison.CurrentCultureIgnoreCase,
        StringComparison.InvariantCulture,
        StringComparison.InvariantCultureIgnoreCase,
        StringComparison.Ordinal,
        StringComparison.OrdinalIgnoreCase };

// Clear the screen and display an introduction.
    Console.Clear();
    Console.WriteLine(intro);

// Display the current culture because culture affects the result. For example, 
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

    Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
    Console.WriteLine("The current culture is \"{0}\" - {1}.", 
                       Thread.CurrentThread.CurrentCulture.Name,
                       Thread.CurrentThread.CurrentCulture.DisplayName);

// Display the string to search for and the string to search.
    Console.WriteLine("Search for the string \"{0}\" in the string \"{1}\"", 
                       CapitalAWithRing, cat);
    Console.WriteLine();

// Note that in each of the following searches, we look for 
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
// the string was not found.
// Search using different values of StringComparison. Specify the start 
// index and count. 

    Console.WriteLine("Part 1: Start index and count are specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. Specify the 
// start index. 
    Console.WriteLine("\nPart 2: Start index is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. 
    Console.WriteLine("\nPart 3: Neither start index nor count is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }
    }
}

/*
Note: This code example was executed on a console whose user interface 
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*/

// This code example demonstrates the
// System.String.IndexOf(String, ..., StringComparison) methods.

open System
open System.Threading
open System.Globalization

let intro = "Find the first occurrence of a character using different values of StringComparison."

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
let CapitalAWithRing = "\u00c5"

// Define a string to search.
// The result of combining the characters LATIN SMALL LETTER A and COMBINING
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
let cat = "A Cheshire c" + "\u0061\u030a" + "t"

let scValues = 
    [| StringComparison.CurrentCulture
       StringComparison.CurrentCultureIgnoreCase
       StringComparison.InvariantCulture
       StringComparison.InvariantCultureIgnoreCase
       StringComparison.Ordinal
       StringComparison.OrdinalIgnoreCase |]

// Clear the screen and display an introduction.
Console.Clear()
printfn $"{intro}"

// Display the current culture because culture affects the result. For example,
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

Thread.CurrentThread.CurrentCulture <- CultureInfo "en-US"
printfn $"The current culture is \"{Thread.CurrentThread.CurrentCulture.Name}\" - {Thread.CurrentThread.CurrentCulture.DisplayName}."

// Display the string to search for and the string to search.
printfn $"Search for the string \"{CapitalAWithRing}\" in the string \"{cat}\"\n"

// Note that in each of the following searches, we look for
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates
// the string was not found.
// Search using different values of StringComparison. Specify the start
// index and count.

printfn "Part 1: Start index and count are specified."
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
    printfn $"Comparison: {sc,-28} Location: {loc,3}"

// Search using different values of StringComparison. Specify the
// start index.
printfn "\nPart 2: Start index is specified."
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, 0, sc)
    printfn $"Comparison: {sc,-28} Location: {loc,3}"

// Search using different values of StringComparison.
Console.WriteLine("\nPart 3: Neither start index nor count is specified.")
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, sc)
    Console.WriteLine("Comparison: {0,-28} Location: {1,3}", sc, loc)

(*
Note: This code example was executed on a console whose user interface
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*)

' This code example demonstrates the 
' System.String.IndexOf(String, ..., StringComparison) methods.

Imports System.Threading
Imports System.Globalization

Class Sample
    Public Shared Sub Main() 
        Dim intro As String = "Find the first occurrence of a character using different " & _
                              "values of StringComparison."
        Dim resultFmt As String = "Comparison: {0,-28} Location: {1,3}"
        
        ' Define a string to search for.
        ' U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
        Dim CapitalAWithRing As String = "Å"
        
        ' Define a string to search. 
        ' The result of combining the characters LATIN SMALL LETTER A and COMBINING 
        ' RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
        ' LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
        Dim cat As String = "A Cheshire c" & "å" & "t"
        
        Dim loc As Integer = 0
        Dim scValues As StringComparison() =  { _
                        StringComparison.CurrentCulture, _
                        StringComparison.CurrentCultureIgnoreCase, _
                        StringComparison.InvariantCulture, _
                        StringComparison.InvariantCultureIgnoreCase, _
                        StringComparison.Ordinal, _
                        StringComparison.OrdinalIgnoreCase }
        Dim sc As StringComparison
        
        ' Clear the screen and display an introduction.
        Console.Clear()
        Console.WriteLine(intro)
        
        ' Display the current culture because culture affects the result. For example, 
        ' try this code example with the "sv-SE" (Swedish-Sweden) culture.
        Thread.CurrentThread.CurrentCulture = New CultureInfo("en-US")
        Console.WriteLine("The current culture is ""{0}"" - {1}.", _
                           Thread.CurrentThread.CurrentCulture.Name, _ 
                           Thread.CurrentThread.CurrentCulture.DisplayName)
        
        ' Display the string to search for and the string to search.
        Console.WriteLine("Search for the string ""{0}"" in the string ""{1}""", _
                           CapitalAWithRing, cat)
        Console.WriteLine()
        
        ' Note that in each of the following searches, we look for 
        ' LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
        ' LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
        ' the string was not found.
        ' Search using different values of StringComparison. Specify the start 
        ' index and count.

        Console.WriteLine("Part 1: Start index and count are specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. Specify the 
        ' start index. 

        Console.WriteLine(vbCrLf & "Part 2: Start index is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. 

        Console.WriteLine(vbCrLf & "Part 3: Neither start index nor count is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
    
    End Sub
End Class

'
'Note: This code example was executed on a console whose user interface 
'culture is "en-US" (English-United States).
'
'This code example produces the following results:
'
'Find the first occurrence of a character using different values of StringComparison.
'The current culture is "en-US" - English (United States).
'Search for the string "Å" in the string "A Cheshire ca°t"
'
'Part 1: Start index and count are specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 2: Start index is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 3: Neither start index nor count is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'

Kommentarer

Indexnumreringen börjar från 0. Parametern startIndex kan variera från 0 till längden på stränginstansen. Om startIndex är lika med längden på stränginstansen returnerar metoden -1.

Parametern comparisonType anger att söka efter parametern value med hjälp av den aktuella eller invarianta kulturen, med hjälp av en skiftlägeskänslig eller skiftlägeskänslig sökning och med hjälp av ord- eller ordningstalsjämförelseregler.

Anteckningar till anropare

Teckenuppsättningar innehåller ignorerbara tecken, som är tecken som inte beaktas när man utför en språklig eller kulturspecifik jämförelse. I en kulturkänslig sökning (dvs. om comparisonType den inte Ordinal är eller OrdinalIgnoreCase), om value den innehåller ett okunnigt tecken, motsvarar resultatet att söka med det tecknet borttaget. Om value endast består av ett eller flera okunniga tecken IndexOf(String, Int32, StringComparison) returnerar startIndexmetoden alltid , vilket är teckenpositionen där sökningen börjar.

I följande exempel IndexOf(String, Int32, StringComparison) används metoden för att hitta positionen för ett mjukt bindestreck (U+00AD) följt av ett "m" som börjar med den tredje teckenpositionen i två strängar. Endast en av strängarna innehåller den delsträng som krävs. Om exemplet körs på .NET Framework 4 eller senare, i båda fallen, eftersom det mjuka bindestrecket är ett okunnigt tecken, returnerar metoden indexet "m" i strängen när den utför en kulturkänslig jämförelse. Observera att när det gäller den första strängen, som innehåller det mjuka bindestrecket följt av ett "m", returnerar metoden inte indexet för det mjuka bindestrecket utan returnerar i stället indexet för "m". Metoden returnerar indexet för det mjuka bindestrecket i den första strängen endast när den utför en ordningsjämförelse.

using System;

public class Example
{
    public static void Main()
    {
      
        string searchString = "\u00ADm";
        string s1 = "ani\u00ADmal" ;
        string s2 = "animal";

        Console.WriteLine(s1.IndexOf(searchString, 2, StringComparison.CurrentCulture));
        Console.WriteLine(s1.IndexOf(searchString, 2, StringComparison.Ordinal));
        Console.WriteLine(s2.IndexOf(searchString, 2, StringComparison.CurrentCulture));
        Console.WriteLine(s2.IndexOf(searchString, 2, StringComparison.Ordinal));

        // The example displays the following output:
        //       4
        //       3
        //       3
        //       -1
    }
}

open System

let searchString = "\u00ADm"
let s1 = "ani\u00ADmal"
let s2 = "animal"

printfn $"{s1.IndexOf(searchString, 2, StringComparison.CurrentCulture)}"
printfn $"{s1.IndexOf(searchString, 2, StringComparison.Ordinal)}"
printfn $"{s2.IndexOf(searchString, 2, StringComparison.CurrentCulture)}"
printfn $"{s2.IndexOf(searchString, 2, StringComparison.Ordinal)}"

// The example displays the following output:
//       4
//       3
//       3
//       -1

Module Example
   Public Sub Main()
      Dim searchString As String = Chrw(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"

      Console.WriteLine(s1.IndexOf(searchString, 2, StringComparison.CurrentCulture))
      Console.WriteLine(s1.IndexOf(searchString, 2, StringComparison.Ordinal))
      Console.WriteLine(s2.IndexOf(searchString, 2, StringComparison.CurrentCulture))
      Console.WriteLine(s2.IndexOf(searchString, 2, StringComparison.Ordinal))
   End Sub
End Module
' The example displays the following output:
'       4
'       3
'       3
'       -1

public:
 int IndexOf(System::String ^ value, int startIndex, int count);

public int IndexOf(string value, int startIndex, int count);

member this.IndexOf : string * int * int -> int

Public Function IndexOf (value As String, startIndex As Integer, count As Integer) As Integer

Parametrar

Returer

Den nollbaserade indexpositionen value för från början av den aktuella instansen om strängen hittas eller -1 om den inte är det. Om value är Emptyär startIndexreturvärdet .

Undantag

Exempel

I följande exempel hittas indexet för alla förekomster av strängen "he" i en delsträng av en annan sträng. Observera att antalet tecken som ska sökas igenom måste beräknas om för varje sök-iteration.

string br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+---";
string br2 = "012345678901234567890123456789012345678901234567890123456789012345678";
string str = "Now is the time for all good men to come to the aid of their country.";
int start;
int at;
int end;
int count;

end = str.Length;
start = end/2;
Console.WriteLine();
Console.WriteLine("All occurrences of 'he' from position {0} to {1}.", start, end-1);
Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str);
Console.Write("The string 'he' occurs at position(s): ");

count = 0;
at = 0;
while((start <= end) && (at > -1))
{
    // start+count must be a position within -str-.
    count = end - start;
    at = str.IndexOf("he", start, count);
    if (at == -1) break;
    Console.Write("{0} ", at);
    start = at+1;
}
Console.WriteLine();

/*
This example produces the following results:

All occurrences of 'he' from position 34 to 68.
0----+----1----+----2----+----3----+----4----+----5----+----6----+---
012345678901234567890123456789012345678901234567890123456789012345678
Now is the time for all good men to come to the aid of their country.

The string 'he' occurs at position(s): 45 56

*/

let br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+---"
let br2 = "012345678901234567890123456789012345678901234567890123456789012345678"
let str = "Now is the time for all good men to come to the aid of their country."

let last = str.Length
let mutable start = last / 2
printfn $"\nAll occurrences of 'he' from position {start} to {last - 1}."
printfn $"{br1}{Environment.NewLine}{br2}{Environment.NewLine}{str}{Environment.NewLine}"
printf "The string 'he' occurs at position(s): "

let mutable broken = false
let mutable at = 0
while (start <= last) && (at > -1) do
    // start+count must be a position within -str-.
    let count = last - start
    at <- str.IndexOf("he", start, count)
    if at = -1 then
        broken <- true
    else
        printf $"{at} "
        start <- at + 1
printfn ""

(*
This example produces the following results:

All occurrences of 'he' from position 34 to 68.
0----+----1----+----2----+----3----+----4----+----5----+----6----+---
012345678901234567890123456789012345678901234567890123456789012345678
Now is the time for all good men to come to the aid of their country.

The string 'he' occurs at position(s): 45 56

*)

' Sample for String.IndexOf(String, Int32, Int32)
Class Sample
   
   Public Shared Sub Main()
      
      Dim br1 As String = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-"
      Dim br2 As String = "0123456789012345678901234567890123456789012345678901234567890123456"
      Dim str As String = "Now is the time for all good men to come to the aid of their party."
      Dim start As Integer
      Dim at As Integer
      Dim [end] As Integer
      Dim count As Integer
      
      [end] = str.Length
      start = [end] / 2
      Console.WriteLine()
      Console.WriteLine("All occurrences of 'he' from position {0} to {1}.", start, [end] - 1)
      Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str)
      Console.Write("The string 'he' occurs at position(s): ")
      
      count = 0
      at = 0
      While start <= [end] AndAlso at > - 1
         ' start+count must be a position within -str-.
         count = [end] - start
         at = str.IndexOf("he", start, count)
         If at = - 1 Then
            Exit While
         End If
         Console.Write("{0} ", at)
         start = at + 1
      End While
      Console.WriteLine()
   End Sub
End Class
'
'This example produces the following results:
'
'All occurrences of 'he' from position 33 to 66.
'0----+----1----+----2----+----3----+----4----+----5----+----6----+-
'0123456789012345678901234567890123456789012345678901234567890123456
'Now is the time for all good men to come to the aid of their party.
'
'The string 'he' occurs at position(s): 45 56
'
'

Kommentarer

Indexnumreringen börjar från 0 (noll). Parametern startIndex kan variera från 0 till längden på stränginstansen.

Den här metoden utför en ordsökning (skiftlägeskänslig och kulturkänslig) med hjälp av den aktuella kulturen. Sökningen börjar vid startIndex och fortsätter till startIndex + count -1. Tecknet på startIndex + count ingår inte i sökningen.

Teckenuppsättningar innehåller ignorerbara tecken, som är tecken som inte beaktas när man utför en språklig eller kulturspecifik jämförelse. I en kulturkänslig sökning, om value innehåller ett okunnigt tecken, motsvarar resultatet att söka med det tecknet borttaget. Om value endast består av ett eller flera okunniga tecken IndexOf(String, Int32, Int32) returnerar startIndexmetoden alltid , vilket är teckenpositionen där sökningen börjar. I följande exempel IndexOf(String, Int32, Int32) används metoden för att hitta positionen för ett mjukt bindestreck (U+00AD) följt av ett "m" med början i den tredje till sjätte teckenpositionen i två strängar. Endast en av strängarna innehåller den delsträng som krävs. Om exemplet körs på .NET Framework 4 eller senare, i båda fallen, eftersom det mjuka bindestrecket är ett okunnigt tecken, returnerar metoden indexet "m" i strängen när den utför en kulturkänslig jämförelse. Observera att när det gäller den första strängen, som innehåller det mjuka bindestrecket följt av ett "m", returnerar metoden inte indexet för det mjuka bindestrecket utan returnerar i stället indexet för "m".

using System;

public class Example
{
    public static void Main()
    {
        string searchString = "\u00ADm";
        string s1 = "ani\u00ADmal" ;
        string s2 = "animal";

        Console.WriteLine(s1.IndexOf(searchString, 2, 4));
        Console.WriteLine(s2.IndexOf(searchString, 2, 4));

        // The example displays the following output:
        //       4
        //       3
    }
}

let searchString = "\u00ADm"
let s1 = "ani\u00ADmal"
let s2 = "animal"

printfn $"{s1.IndexOf(searchString, 2, 4)}"
printfn $"{s2.IndexOf(searchString, 2, 4)}"

// The example displays the following output:
//       4
//       3

Module Example
   Public Sub Main()
      Dim searchString As String = Chrw(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"

      Console.WriteLine(s1.IndexOf(searchString, 2, 4))
      Console.WriteLine(s2.IndexOf(searchString, 2, 4))
   End Sub
End Module
' The example displays the following output:
'       4
'       3

Anteckningar till anropare

Som beskrivs i Metodtips för att använda strängar rekommenderar vi att du undviker att anropa strängjämförelsemetoder som ersätter standardvärden och i stället anropar metoder som kräver att parametrar uttryckligen anges. Om du vill använda jämförelsereglerna för den aktuella kulturen för att utföra den här åtgärden ska du uttryckligen signalera din avsikt genom att anropa IndexOf(String, Int32, Int32, StringComparison) metodens överlagring med värdet CurrentCulture för för dess comparisonType parameter. Om du inte behöver en språkmedveten jämförelse bör du överväga att använda Ordinal.

Se även

• Int32
• CultureInfo
• IndexOfAny(Char[])
• LastIndexOf(Char)
• LastIndexOfAny(Char[])

public:
 int IndexOf(char value, int startIndex, int count);

public int IndexOf(char value, int startIndex, int count);

member this.IndexOf : char * int * int -> int

Public Function IndexOf (value As Char, startIndex As Integer, count As Integer) As Integer

Parametrar

Returer

Den nollbaserade indexpositionen value för från början av strängen om det tecknet hittas eller -1 om det inte är det.

Undantag

Exempel

I följande exempel visas IndexOf metoden.

// Example for the String.IndexOf( char, int, int ) method.
using System;

class IndexOfCII 
{
    public static void Main() 
    {
        string br1 = 
            "0----+----1----+----2----+----3----+----" +
            "4----+----5----+----6----+----7";
        string br2 = 
            "0123456789012345678901234567890123456789" +
            "0123456789012345678901234567890";
        string str = 
            "ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi " +
            "ABCDEFGHI abcdefghi ABCDEFGHI";

        Console.WriteLine( 
            "This example of String.IndexOf( char, int, int )\n" +
            "generates the following output." );
        Console.WriteLine( 
            "{0}{1}{0}{2}{0}{3}{0}", 
            Environment.NewLine, br1, br2, str );

        FindAllChar( 'A', str );
        FindAllChar( 'a', str );
        FindAllChar( 'I', str );
        FindAllChar( 'i', str );
        FindAllChar( '@', str );
        FindAllChar( ' ', str );
    }

    static void FindAllChar( Char target, String searched )
    {
        Console.Write( 
            "The character '{0}' occurs at position(s): ", 
            target );

        int     startIndex = -1;
        int     hitCount = 0;

        // Search for all occurrences of the target.
        while( true )
        {
            startIndex = searched.IndexOf( 
                target, startIndex + 1, 
                searched.Length - startIndex - 1 );

            // Exit the loop if the target is not found.
            if( startIndex < 0 )
                break;

            Console.Write( "{0}, ", startIndex );
            hitCount++;
        }

        Console.WriteLine( "occurrences: {0}", hitCount );
    }
}

/*
This example of String.IndexOf( char, int, int )
generates the following output.

0----+----1----+----2----+----3----+----4----+----5----+----6----+----7
01234567890123456789012345678901234567890123456789012345678901234567890
ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI

The character 'A' occurs at position(s): 0, 20, 40, 60, occurrences: 4
The character 'a' occurs at position(s): 10, 30, 50, occurrences: 3
The character 'I' occurs at position(s): 8, 28, 48, 68, occurrences: 4
The character 'i' occurs at position(s): 18, 38, 58, occurrences: 3
The character '@' occurs at position(s): occurrences: 0
The character ' ' occurs at position(s): 9, 19, 29, 39, 49, 59, occurrences: 6
*/

// Example for the String.IndexOf( char, int, int ) method.
open System

let br1 =
    "0----+----1----+----2----+----3----+----" +
    "4----+----5----+----6----+----7"
let br2 =
    "0123456789012345678901234567890123456789" +
    "0123456789012345678901234567890"
let str =
    "ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi " +
    "ABCDEFGHI abcdefghi ABCDEFGHI"

printfn "This example of String.IndexOf( char, int, int )\ngenerates the following output."
printfn $"{Environment.NewLine}{br1}{Environment.NewLine}{br2}{Environment.NewLine}{str}{Environment.NewLine}"

let findAllChar (target: char) (searched: string) =
    printf $"The character '{target}' occurs at position(s): "

    let mutable hitCount = 0
    let mutable startIndex = -1
    let mutable broken = false
    // Search for all occurrences of the target.
    while not broken do
        startIndex <- searched.IndexOf(target, startIndex + 1, searched.Length - startIndex - 1)

        // Exit the loop if the target is not found.
        if startIndex < 0 then
            broken <- true
        else

        printf $"{startIndex}, "
        hitCount <- hitCount + 1

    printfn $"occurrences: {hitCount}"

findAllChar 'A' str
findAllChar 'a' str
findAllChar 'I' str
findAllChar 'i' str
findAllChar '@' str
findAllChar ' ' str


(*
This example of String.IndexOf( char, int, int )
generates the following output.

0----+----1----+----2----+----3----+----4----+----5----+----6----+----7
01234567890123456789012345678901234567890123456789012345678901234567890
ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI

The character 'A' occurs at position(s): 0, 20, 40, 60, occurrences: 4
The character 'a' occurs at position(s): 10, 30, 50, occurrences: 3
The character 'I' occurs at position(s): 8, 28, 48, 68, occurrences: 4
The character 'i' occurs at position(s): 18, 38, 58, occurrences: 3
The character '@' occurs at position(s): occurrences: 0
The character ' ' occurs at position(s): 9, 19, 29, 39, 49, 59, occurrences: 6
*)

' Example for the String.IndexOf( Char, Integer, Integer ) method.
Module IndexOfCII
   
    Sub Main()
        Dim br1 As String = _
            "0----+----1----+----2----+----3----+----" & _
            "4----+----5----+----6----+----7"
        Dim br2 As String = _
            "0123456789012345678901234567890123456789" & _
            "0123456789012345678901234567890"
        Dim str As String = _
            "ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi " & _
            "ABCDEFGHI abcdefghi ABCDEFGHI"
          
        Console.WriteLine( _
            "This example of String.IndexOf( Char, Integer, Integer )" & _
            vbCrLf & "generates the following output." )
        Console.WriteLine( _
            "{0}{1}{0}{2}{0}{3}{0}", _
            Environment.NewLine, br1, br2, str)

        FindAllChar("A"c, str)
        FindAllChar("a"c, str)
        FindAllChar("I"c, str)
        FindAllChar("i"c, str)
        FindAllChar("@"c, str)
        FindAllChar(" "c, str)
    End Sub
       
    Sub FindAllChar(target As Char, searched As String)

        Console.Write( _
            "The character ""{0}"" occurs at position(s): ", target)
          
        Dim startIndex As Integer = - 1
        Dim hitCount As Integer = 0
          
        ' Search for all occurrences of the target.
        While True
            startIndex = searched.IndexOf( _
                target, startIndex + 1, _
                searched.Length - startIndex - 1)

            ' Exit the loop if the target is not found.
            If startIndex < 0 Then
                Exit While
            End If 

            Console.Write("{0}, ", startIndex)
            hitCount += 1
        End While
          
        Console.WriteLine("occurrences: {0}", hitCount)

    End Sub
End Module 'IndexOfCII

' This example of String.IndexOf( Char, Integer, Integer )
' generates the following output.
' 
' 0----+----1----+----2----+----3----+----4----+----5----+----6----+----7
' 01234567890123456789012345678901234567890123456789012345678901234567890
' ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI abcdefghi ABCDEFGHI
' 
' The character "A" occurs at position(s): 0, 20, 40, 60, occurrences: 4
' The character "a" occurs at position(s): 10, 30, 50, occurrences: 3
' The character "I" occurs at position(s): 8, 28, 48, 68, occurrences: 4
' The character "i" occurs at position(s): 18, 38, 58, occurrences: 3
' The character "@" occurs at position(s): occurrences: 0
' The character " " occurs at position(s): 9, 19, 29, 39, 49, 59, occurrences: 6

Kommentarer

Sökningen börjar vid startIndex och fortsätter till startIndex + count -1. Tecknet på startIndex + count ingår inte i sökningen.

Indexnumreringen börjar från 0 (noll). Parametern startIndex kan variera från 0 till längden på stränginstansen.

Den här metoden utför en ordningstalssökning (kulturokänslig) där ett tecken endast anses motsvara ett annat tecken om deras Unicode-skalärvärden är desamma. Om du vill utföra en kulturkänslig sökning använder du CompareInfo.IndexOf metoden, där ett Unicode-skalärt värde som representerar ett förkomponerat tecken, till exempel ligaturen "Æ" (U+00C6), kan anses motsvara alla förekomster av tecknets komponenter i rätt sekvens, till exempel "AE" (U+0041, U+0045), beroende på kulturen.

Se även

• Char
• Int32
• IndexOfAny(Char[])
• LastIndexOf(Char)
• LastIndexOfAny(Char[])

public:
 int IndexOf(System::String ^ value, StringComparison comparisonType);

public int IndexOf(string value, StringComparison comparisonType);

member this.IndexOf : string * StringComparison -> int

Public Function IndexOf (value As String, comparisonType As StringComparison) As Integer

Parametrar

Returer

Indexpositionen för parametern om strängen value hittas eller -1 om den inte är det. I value så Emptyfall är returvärdet 0.

Undantag

Exempel

I följande exempel visas tre överlagringar av IndexOf metoden som hittar den första förekomsten av en sträng i en annan sträng med hjälp av olika värden för StringComparison uppräkningen.

// This code example demonstrates the 
// System.String.IndexOf(String, ..., StringComparison) methods.

using System;
using System.Threading;
using System.Globalization;

class Sample 
{
    public static void Main() 
    {
    string intro = "Find the first occurrence of a character using different " + 
                   "values of StringComparison.";
    string resultFmt = "Comparison: {0,-28} Location: {1,3}";

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
    string CapitalAWithRing = "\u00c5"; 

// Define a string to search. 
// The result of combining the characters LATIN SMALL LETTER A and COMBINING 
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
    string cat = "A Cheshire c" + "\u0061\u030a" + "t";

    int loc = 0;
    StringComparison[] scValues = {
        StringComparison.CurrentCulture,
        StringComparison.CurrentCultureIgnoreCase,
        StringComparison.InvariantCulture,
        StringComparison.InvariantCultureIgnoreCase,
        StringComparison.Ordinal,
        StringComparison.OrdinalIgnoreCase };

// Clear the screen and display an introduction.
    Console.Clear();
    Console.WriteLine(intro);

// Display the current culture because culture affects the result. For example, 
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

    Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
    Console.WriteLine("The current culture is \"{0}\" - {1}.", 
                       Thread.CurrentThread.CurrentCulture.Name,
                       Thread.CurrentThread.CurrentCulture.DisplayName);

// Display the string to search for and the string to search.
    Console.WriteLine("Search for the string \"{0}\" in the string \"{1}\"", 
                       CapitalAWithRing, cat);
    Console.WriteLine();

// Note that in each of the following searches, we look for 
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
// the string was not found.
// Search using different values of StringComparison. Specify the start 
// index and count. 

    Console.WriteLine("Part 1: Start index and count are specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. Specify the 
// start index. 
    Console.WriteLine("\nPart 2: Start index is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, 0, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }

// Search using different values of StringComparison. 
    Console.WriteLine("\nPart 3: Neither start index nor count is specified.");
    foreach (StringComparison sc in scValues)
        {
        loc = cat.IndexOf(CapitalAWithRing, sc);
        Console.WriteLine(resultFmt, sc, loc);
        }
    }
}

/*
Note: This code example was executed on a console whose user interface 
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*/

// This code example demonstrates the
// System.String.IndexOf(String, ..., StringComparison) methods.

open System
open System.Threading
open System.Globalization

let intro = "Find the first occurrence of a character using different values of StringComparison."

// Define a string to search for.
// U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
let CapitalAWithRing = "\u00c5"

// Define a string to search.
// The result of combining the characters LATIN SMALL LETTER A and COMBINING
// RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character
// LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
let cat = "A Cheshire c" + "\u0061\u030a" + "t"

let scValues = 
    [| StringComparison.CurrentCulture
       StringComparison.CurrentCultureIgnoreCase
       StringComparison.InvariantCulture
       StringComparison.InvariantCultureIgnoreCase
       StringComparison.Ordinal
       StringComparison.OrdinalIgnoreCase |]

// Clear the screen and display an introduction.
Console.Clear()
printfn $"{intro}"

// Display the current culture because culture affects the result. For example,
// try this code example with the "sv-SE" (Swedish-Sweden) culture.

Thread.CurrentThread.CurrentCulture <- CultureInfo "en-US"
printfn $"The current culture is \"{Thread.CurrentThread.CurrentCulture.Name}\" - {Thread.CurrentThread.CurrentCulture.DisplayName}."

// Display the string to search for and the string to search.
printfn $"Search for the string \"{CapitalAWithRing}\" in the string \"{cat}\"\n"

// Note that in each of the following searches, we look for
// LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains
// LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates
// the string was not found.
// Search using different values of StringComparison. Specify the start
// index and count.

printfn "Part 1: Start index and count are specified."
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
    printfn $"Comparison: {sc,-28} Location: {loc,3}"

// Search using different values of StringComparison. Specify the
// start index.
printfn "\nPart 2: Start index is specified."
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, 0, sc)
    printfn $"Comparison: {sc,-28} Location: {loc,3}"

// Search using different values of StringComparison.
Console.WriteLine("\nPart 3: Neither start index nor count is specified.")
for sc in scValues do
    let loc = cat.IndexOf(CapitalAWithRing, sc)
    Console.WriteLine("Comparison: {0,-28} Location: {1,3}", sc, loc)

(*
Note: This code example was executed on a console whose user interface
culture is "en-US" (English-United States).

This code example produces the following results:

Find the first occurrence of a character using different values of StringComparison.
The current culture is "en-US" - English (United States).
Search for the string "Å" in the string "A Cheshire ca°t"

Part 1: Start index and count are specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 2: Start index is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

Part 3: Neither start index nor count is specified.
Comparison: CurrentCulture               Location:  -1
Comparison: CurrentCultureIgnoreCase     Location:  12
Comparison: InvariantCulture             Location:  -1
Comparison: InvariantCultureIgnoreCase   Location:  12
Comparison: Ordinal                      Location:  -1
Comparison: OrdinalIgnoreCase            Location:  -1

*)

' This code example demonstrates the 
' System.String.IndexOf(String, ..., StringComparison) methods.

Imports System.Threading
Imports System.Globalization

Class Sample
    Public Shared Sub Main() 
        Dim intro As String = "Find the first occurrence of a character using different " & _
                              "values of StringComparison."
        Dim resultFmt As String = "Comparison: {0,-28} Location: {1,3}"
        
        ' Define a string to search for.
        ' U+00c5 = LATIN CAPITAL LETTER A WITH RING ABOVE
        Dim CapitalAWithRing As String = "Å"
        
        ' Define a string to search. 
        ' The result of combining the characters LATIN SMALL LETTER A and COMBINING 
        ' RING ABOVE (U+0061, U+030a) is linguistically equivalent to the character 
        ' LATIN SMALL LETTER A WITH RING ABOVE (U+00e5).
        Dim cat As String = "A Cheshire c" & "å" & "t"
        
        Dim loc As Integer = 0
        Dim scValues As StringComparison() =  { _
                        StringComparison.CurrentCulture, _
                        StringComparison.CurrentCultureIgnoreCase, _
                        StringComparison.InvariantCulture, _
                        StringComparison.InvariantCultureIgnoreCase, _
                        StringComparison.Ordinal, _
                        StringComparison.OrdinalIgnoreCase }
        Dim sc As StringComparison
        
        ' Clear the screen and display an introduction.
        Console.Clear()
        Console.WriteLine(intro)
        
        ' Display the current culture because culture affects the result. For example, 
        ' try this code example with the "sv-SE" (Swedish-Sweden) culture.
        Thread.CurrentThread.CurrentCulture = New CultureInfo("en-US")
        Console.WriteLine("The current culture is ""{0}"" - {1}.", _
                           Thread.CurrentThread.CurrentCulture.Name, _ 
                           Thread.CurrentThread.CurrentCulture.DisplayName)
        
        ' Display the string to search for and the string to search.
        Console.WriteLine("Search for the string ""{0}"" in the string ""{1}""", _
                           CapitalAWithRing, cat)
        Console.WriteLine()
        
        ' Note that in each of the following searches, we look for 
        ' LATIN CAPITAL LETTER A WITH RING ABOVE in a string that contains 
        ' LATIN SMALL LETTER A WITH RING ABOVE. A result value of -1 indicates 
        ' the string was not found.
        ' Search using different values of StringComparison. Specify the start 
        ' index and count.

        Console.WriteLine("Part 1: Start index and count are specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, cat.Length, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. Specify the 
        ' start index. 

        Console.WriteLine(vbCrLf & "Part 2: Start index is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, 0, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
        
        ' Search using different values of StringComparison. 

        Console.WriteLine(vbCrLf & "Part 3: Neither start index nor count is specified.")
        For Each sc In  scValues
            loc = cat.IndexOf(CapitalAWithRing, sc)
            Console.WriteLine(resultFmt, sc, loc)
        Next sc
    
    End Sub
End Class

'
'Note: This code example was executed on a console whose user interface 
'culture is "en-US" (English-United States).
'
'This code example produces the following results:
'
'Find the first occurrence of a character using different values of StringComparison.
'The current culture is "en-US" - English (United States).
'Search for the string "Å" in the string "A Cheshire ca°t"
'
'Part 1: Start index and count are specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 2: Start index is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'
'Part 3: Neither start index nor count is specified.
'Comparison: CurrentCulture               Location:  -1
'Comparison: CurrentCultureIgnoreCase     Location:  12
'Comparison: InvariantCulture             Location:  -1
'Comparison: InvariantCultureIgnoreCase   Location:  12
'Comparison: Ordinal                      Location:  -1
'Comparison: OrdinalIgnoreCase            Location:  -1
'

Kommentarer

Indexnumreringen börjar från noll.

Parametern comparisonType anger att söka efter parametern value med hjälp av den aktuella eller invarianta kulturen, med hjälp av en skiftlägeskänslig eller skiftlägeskänslig sökning och med hjälp av ord- eller ordningstalsjämförelseregler.

Anteckningar till anropare

Teckenuppsättningar innehåller ignorerbara tecken, som är tecken som inte beaktas när man utför en språklig eller kulturspecifik jämförelse. I en kulturkänslig sökning (dvs. om comparisonType den inte Ordinal är eller OrdinalIgnoreCase), om value den innehåller ett okunnigt tecken, motsvarar resultatet att söka med det tecknet borttaget. Om value endast består av ett eller flera okunniga tecken IndexOf(String, StringComparison) returnerar metoden alltid 0 (noll) för att indikera att matchningen hittas i början av den aktuella instansen.

I följande exempel IndexOf(String, StringComparison) används metoden för att hitta tre understrängar (ett mjukt bindestreck (U+00AD), ett mjukt bindestreck följt av "n" och ett mjukt bindestreck följt av "m") i två strängar. Endast en av strängarna innehåller ett mjukt bindestreck. Om exemplet körs på .NET Framework 4 eller senare, eftersom det mjuka bindestrecket är ett okunnigt tecken, returnerar en kulturkänslig sökning samma värde som den skulle returnera om det mjuka bindestrecket inte ingick i söksträngen. En ordningssökning hittar dock det mjuka bindestrecket i en sträng och rapporterar att det saknas från den andra strängen.

using System;

public class Example
{
    public static void Main()
    {
        string s1 = "ani\u00ADmal";
        string s2 = "animal";
      
        Console.WriteLine("Culture-sensitive comparison:");
        // Use culture-sensitive comparison to find the soft hyphen.
        Console.WriteLine(s1.IndexOf("\u00AD", StringComparison.CurrentCulture));
        Console.WriteLine(s2.IndexOf("\u00AD", StringComparison.CurrentCulture));
      
        // Use culture-sensitive comparison to find the soft hyphen followed by "n".
        Console.WriteLine(s1.IndexOf("\u00ADn", StringComparison.CurrentCulture));
        Console.WriteLine(s2.IndexOf("\u00ADn", StringComparison.CurrentCulture));
      
        // Use culture-sensitive comparison to find the soft hyphen followed by "m".
        Console.WriteLine(s1.IndexOf("\u00ADm", StringComparison.CurrentCulture));
        Console.WriteLine(s2.IndexOf("\u00ADm", StringComparison.CurrentCulture));
      
        Console.WriteLine("Ordinal comparison:");
        // Use ordinal comparison to find the soft hyphen.
        Console.WriteLine(s1.IndexOf("\u00AD", StringComparison.Ordinal));
        Console.WriteLine(s2.IndexOf("\u00AD", StringComparison.Ordinal));
      
        // Use ordinal comparison to find the soft hyphen followed by "n".
        Console.WriteLine(s1.IndexOf("\u00ADn", StringComparison.Ordinal));
        Console.WriteLine(s2.IndexOf("\u00ADn", StringComparison.Ordinal));
      
        // Use ordinal comparison to find the soft hyphen followed by "m".
        Console.WriteLine(s1.IndexOf("\u00ADm", StringComparison.Ordinal));
        Console.WriteLine(s2.IndexOf("\u00ADm", StringComparison.Ordinal));

        // The example displays the following output:
        //       Culture-sensitive comparison:
        //       0
        //       0
        //       1
        //       1
        //       4
        //       3
        //       Ordinal comparison:
        //       3
        //       -1
        //       -1
        //       -1
        //       3
        //       -1
    }
}

open System

let s1 = "ani\u00ADmal"
let s2 = "animal"

printfn "Culture-sensitive comparison:"
// Use culture-sensitive comparison to find the soft hyphen.
printfn $"""{s1.IndexOf("\u00AD", StringComparison.CurrentCulture)}"""
printfn $"""{s2.IndexOf("\u00AD", StringComparison.CurrentCulture)}"""

// Use culture-sensitive comparison to find the soft hyphen followed by "n".
printfn $"""{s1.IndexOf("\u00ADn", StringComparison.CurrentCulture)}"""
printfn $"""{s2.IndexOf("\u00ADn", StringComparison.CurrentCulture)}"""

// Use culture-sensitive comparison to find the soft hyphen followed by "m".
printfn $"""{s1.IndexOf("\u00ADm", StringComparison.CurrentCulture)}"""
printfn $"""{s2.IndexOf("\u00ADm", StringComparison.CurrentCulture)}"""

printfn "Ordinal comparison:"
// Use ordinal comparison to find the soft hyphen.
printfn $"""{s1.IndexOf("\u00AD", StringComparison.Ordinal)}"""
printfn $"""{s2.IndexOf("\u00AD", StringComparison.Ordinal)}"""

// Use ordinal comparison to find the soft hyphen followed by "n".
printfn $"""{s1.IndexOf("\u00ADn", StringComparison.Ordinal)}"""
printfn $"""{s2.IndexOf("\u00ADn", StringComparison.Ordinal)}"""

// Use ordinal comparison to find the soft hyphen followed by "m".
printfn $"""{s1.IndexOf("\u00ADm", StringComparison.Ordinal)}"""
printfn $"""{s2.IndexOf("\u00ADm", StringComparison.Ordinal)}"""

// The example displays the following output:
//       Culture-sensitive comparison:
//       0
//       0
//       1
//       1
//       4
//       3
//       Ordinal comparison:
//       3
//       -1
//       -1
//       -1
//       3
//       -1

Module Example
   Public Sub Main()
      Dim softHyphen As String = ChrW(&h00AD)
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      Console.WriteLine("Culture-sensitive comparison:")
      ' Use culture-sensitive comparison to find the soft hyphen.
      Console.WriteLine(s1.IndexOf(softHyphen, StringComparison.CurrentCulture))
      Console.WriteLine(s2.IndexOf(softHyphen, StringComparison.CurrentCulture))
      
      ' Use culture-sensitive comparison to find the soft hyphen followed by "n".
      Console.WriteLine(s1.IndexOf(softHyphen + "n", StringComparison.CurrentCulture))
      Console.WriteLine(s2.IndexOf(softHyphen + "n", StringComparison.CurrentCulture))
      
      ' Use culture-sensitive comparison to find the soft hyphen followed by "m".
      Console.WriteLine(s1.IndexOf(softHyphen + "m", StringComparison.CurrentCulture))
      Console.WriteLine(s2.IndexOf(softHyphen + "m", StringComparison.CurrentCulture))
      
      Console.WriteLine("Ordinal comparison:")
      ' Use ordinal comparison to find the soft hyphen.
      Console.WriteLine(s1.IndexOf(softHyphen, StringComparison.Ordinal))
      Console.WriteLine(s2.IndexOf(softHyphen, StringComparison.Ordinal))
      
      ' Use ordinal comparison to find the soft hyphen followed by "n".
      Console.WriteLine(s1.IndexOf(softHyphen + "n", StringComparison.Ordinal))
      Console.WriteLine(s2.IndexOf(softHyphen + "n", StringComparison.Ordinal))
      
      ' Use ordinal comparison to find the soft hyphen followed by "m".
      Console.WriteLine(s1.IndexOf(softHyphen + "m", StringComparison.Ordinal))
      Console.WriteLine(s2.IndexOf(softHyphen + "m", StringComparison.Ordinal))
   End Sub
End Module
' The example displays the following output:
'       Culture-sensitive comparison:
'       0
'       0
'       1
'       1
'       4
'       3
'       Ordinal comparison:
'       3
'       -1
'       -1
'       -1
'       3
'       -1

public:
 int IndexOf(char value);

public int IndexOf(char value);

member this.IndexOf : char -> int

Public Function IndexOf (value As Char) As Integer

Parametrar

Returer

Den nollbaserade indexpositionen value för om det tecknet hittas eller -1 om det inte är det.

Exempel

I följande exempel visas hur du kan söka efter String ett tecken med hjälp av IndexOf metoden.

// Create a Unicode string with 5 Greek Alpha characters.
String szGreekAlpha = new String('\u0391',5);

// Create a Unicode string with 3 Greek Omega characters.
String szGreekOmega = "\u03A9\u03A9\u03A9";

String szGreekLetters = String.Concat(szGreekOmega, szGreekAlpha, 
                                    szGreekOmega.Clone());

// Display the entire string.
Console.WriteLine("The string: {0}", szGreekLetters);

// The first index of Alpha.
int ialpha = szGreekLetters.IndexOf('\u0391');
// The first index of Omega.
int iomega = szGreekLetters.IndexOf('\u03A9');

Console.WriteLine("First occurrence of the Greek letter Alpha: Index {0}", 
                ialpha);
Console.WriteLine("First occurrence of the Greek letter Omega: Index {0}", 
                iomega);

// The example displays the following output:
//    The string: ΩΩΩΑΑΑΑΑΩΩΩ
//    First occurrence of the Greek letter Alpha: Index 3
//    First occurrence of the Greek letter Omega: Index 0

open System

// Create a Unicode string with 5 Greek Alpha characters.
let szGreekAlpha = String('\u0391',5)

// Create a Unicode string with 3 Greek Omega characters.
let szGreekOmega = "\u03A9\u03A9\u03A9"

let szGreekLetters = String.Concat(szGreekOmega, szGreekAlpha, szGreekOmega.Clone())

// Display the entire string.
printfn $"The string: {szGreekLetters}"

// The first index of Alpha.
let ialpha = szGreekLetters.IndexOf '\u0391'
// The first index of Omega.
let iomega = szGreekLetters.IndexOf '\u03A9'

printfn "First occurrence of the Greek letter Alpha: Index {ialpha}"
printfn "First occurrence of the Greek letter Omega: Index {iomega}"

// The example displays the following output:
//    The string: ΩΩΩΑΑΑΑΑΩΩΩ
//    First occurrence of the Greek letter Alpha: Index 3
//    First occurrence of the Greek letter Omega: Index 0

Public Module Example
   Public Sub Main()
      ' Create a Unicode string with 5 Greek Alpha characters.
      Dim szGreekAlpha As New String(ChrW(&H0391), 5)

      ' Create a Unicode string with 3 Greek Omega characters.
      Dim szGreekOmega As String = ChrW(&H03A9) + ChrW(&H03A9)+
                                   ChrW(&H03A9)

      Dim szGreekLetters As String = String.Concat(szGreekOmega, szGreekAlpha, _
                                                   szGreekOmega.Clone())

      ' Display the entire string.
      Console.WriteLine(szGreekLetters)

      ' The first index of Alpha.
      Dim iAlpha As Integer = szGreekLetters.IndexOf(ChrW(&H0391))
      ' The first index of Omega.
      Dim iomega As Integer = szGreekLetters.IndexOf(ChrW(&H03A9))

      Console.WriteLine("First occurrence of the Greek letter Alpha: Index {0}", 
                        ialpha)
      Console.WriteLine("First occurrence of the Greek letter Omega: Index {0}", 
                        iomega)
   End Sub
End Module
' The example displays the following output:
'       The string: OOO?????OOO
'       First occurrence of the Greek letter Alpha: Index 3
'       First occurrence of the Greek letter Omega: Index 0

Kommentarer

Indexnumreringen börjar från noll.

Den här metoden utför en ordningstalssökning (kulturokänslig) där ett tecken endast anses motsvara ett annat tecken om deras Unicode-skalärvärden är desamma. Om du vill utföra en kulturkänslig sökning använder du CompareInfo.IndexOf metoden, där ett Unicode-skalärt värde som representerar ett förkomponerat tecken, till exempel ligaturen "Æ" (U+00C6), kan anses motsvara alla förekomster av tecknets komponenter i rätt sekvens, till exempel "AE" (U+0041, U+0045), beroende på kulturen.

Se även

• Char
• IndexOfAny(Char[])
• LastIndexOf(Char)
• LastIndexOfAny(Char[])

public:
 int IndexOf(char value, StringComparison comparisonType);

public int IndexOf(char value, StringComparison comparisonType);

member this.IndexOf : char * StringComparison -> int

Public Function IndexOf (value As Char, comparisonType As StringComparison) As Integer

Parametrar

Returer

Det nollbaserade indexet för value om det tecknet hittas eller -1 om det inte är det.

Undantag

Kommentarer

Indexnumreringen börjar från noll.

Parametern comparisonType är en StringComparison uppräkningsmedlem som anger om sökningen value efter argumentet använder den aktuella eller invarianta kulturen, är skiftlägeskänslig eller skiftlägeskänslig eller använder ord- eller ordningstalsjämförelseregler.

public:
 int IndexOf(char value, int startIndex);

public int IndexOf(char value, int startIndex);

member this.IndexOf : char * int -> int

Public Function IndexOf (value As Char, startIndex As Integer) As Integer

Parametrar

Returer

Den nollbaserade indexpositionen value för från början av strängen om det tecknet hittas eller -1 om det inte är det.

Undantag

Exempel

I följande exempel visas IndexOf metoden.

string br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+---";
string br2 = "012345678901234567890123456789012345678901234567890123456789012345678";
string str = "Now is the time for all good men to come to the aid of their country.";
int start;
int at;

Console.WriteLine();
Console.WriteLine("All occurrences of 't' from position 0 to {0}.", str.Length-1);
Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str);
Console.Write("The letter 't' occurs at position(s): ");

at = 0;
start = 0;
while((start < str.Length) && (at > -1))
{
    at = str.IndexOf('t', start);
    if (at == -1) break;
    Console.Write("{0} ", at);
    start = at+1;
}
Console.WriteLine();

/*
This example produces the following results:

All occurrences of 't' from position 0 to 68.
0----+----1----+----2----+----3----+----4----+----5----+----6----+---
012345678901234567890123456789012345678901234567890123456789012345678
Now is the time for all good men to come to the aid of their country.

The letter 't' occurs at position(s): 7 11 33 41 44 55 65

*/

let br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+---"
let br2 = "012345678901234567890123456789012345678901234567890123456789012345678"
let str = "Now is the time for all good men to come to the aid of their country."

printfn ""
printfn $"All occurrences of 't' from position 0 to {str.Length - 1}."
printfn $"{br1}{Environment.NewLine}{br2}{Environment.NewLine}{str}{Environment.NewLine}"
printf "The letter 't' occurs at position(s): "

let mutable at = 0
let mutable start = 0
let mutable broken = false
while not broken && (start < str.Length) && (at > -1) do
    at <- str.IndexOf('t', start)
    if at = -1 then broken <- true
    else
        printf $"{at} "
        start <- at + 1
    printfn ""

(*
This example produces the following results:

All occurrences of 't' from position 0 to 68.
0----+----1----+----2----+----3----+----4----+----5----+----6----+---
012345678901234567890123456789012345678901234567890123456789012345678
Now is the time for all good men to come to the aid of their country.

The letter 't' occurs at position(s): 7 11 33 41 44 55 65

*)

' Sample for String.IndexOf(Char, Int32)

Module Sample
    Sub Main()

        Dim br1 As String = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-"
        Dim br2 As String = "0123456789012345678901234567890123456789012345678901234567890123456"
        Dim str As String = "Now is the time for all good men to come to the aid of their party."
        Dim start As Integer
        Dim at As Integer

        Console.WriteLine()
        Console.WriteLine("All occurrences of 't' from position 0 to {0}.", str.Length - 1)
        Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str)
        Console.Write("The letter 't' occurs at position(s): ")

        at = 0
        start = 0
        While start < str.Length AndAlso at > -1
            at = str.IndexOf("t"c, start)
            If at = -1 Then
                Exit While
            End If
            Console.Write("{0} ", at)
            start = at + 1
        End While
        Console.WriteLine()
    End Sub
End Module
'
'This example produces the following results:
'
'All occurrences of 't' from position 0 to 66.
'0----+----1----+----2----+----3----+----4----+----5----+----6----+-
'0123456789012345678901234567890123456789012345678901234567890123456
'Now is the time for all good men to come to the aid of their party.
'
'The letter 't' occurs at position(s): 7 11 33 41 44 55 64
'
'

Kommentarer

Indexnumreringen börjar från 0. Parametern startIndex kan variera från 0 till längden på stränginstansen. Om startIndex är lika med längden på stränginstansen returnerar metoden -1.

Sökningen sträcker sig från startIndex till slutet av strängen.

Den här metoden utför en ordningstalssökning (kulturokänslig) där ett tecken endast anses motsvara ett annat tecken om deras Unicode-skalärvärden är desamma. Om du vill utföra en kulturkänslig sökning använder du CompareInfo.IndexOf metoden, där ett Unicode-skalärt värde som representerar ett förkomponerat tecken, till exempel ligaturen "Æ" (U+00C6), kan anses motsvara alla förekomster av tecknets komponenter i rätt sekvens, till exempel "AE" (U+0041, U+0045), beroende på kulturen.

Se även

• Int32
• Char
• IndexOfAny(Char[])
• LastIndexOf(Char)
• LastIndexOfAny(Char[])

public:
 int IndexOf(System::String ^ value);

public int IndexOf(string value);

member this.IndexOf : string -> int

Public Function IndexOf (value As String) As Integer

Parametrar

Returer

Den nollbaserade indexpositionen value för om strängen hittas eller -1 om den inte är det. I value så Emptyfall är returvärdet 0.

Undantag

Exempel

Följande exempel söker efter "n" i "animal". Eftersom strängindex börjar på noll i stället för ett, IndexOf(String) anger metoden att "n" är på position 1.

String str = "animal";
String toFind = "n";
int index = str.IndexOf("n");
Console.WriteLine("Found '{0}' in '{1}' at position {2}",
                toFind, str, index);

// The example displays the following output:
//        Found 'n' in 'animal' at position 1

open System

let str = "animal"
let toFind = "n"
let index = str.IndexOf "n"
printfn $"Found '{toFind}' in '{str}' at position {index}"

// The example displays the following output:
//        Found 'n' in 'animal' at position 1

Public Module Example
   Public Sub Main()
      Dim str As String = "animal"
      Dim toFind As String = "n"
      Dim index As Integer = str.IndexOf("n")
      Console.WriteLine("Found '{0}' in '{1}' at position {2}",
                        toFind, str, index)
   End Sub
End Module
' The example displays the following output:
'       Found 'n' in 'animal' at position 1

I följande exempel används IndexOf metoden för att fastställa startpositionen för ett djurnamn i en mening. Den använder sedan den här positionen för att infoga ett adjektiv som beskriver djuret i meningen.

using System;

public class Example {
    public static void Main()
    {
        string animal1 = "fox";
        string animal2 = "dog";

        string strTarget = String.Format("The {0} jumps over the {1}.",
                                         animal1, animal2);

        Console.WriteLine("The original string is:{0}{1}{0}",
                          Environment.NewLine, strTarget);

        Console.Write("Enter an adjective (or group of adjectives) " +
                      "to describe the {0}: ==> ", animal1);
        string adj1 = Console.ReadLine();

        Console.Write("Enter an adjective (or group of adjectives) " +
                      "to describe the {0}: ==> ", animal2);
        string adj2 = Console.ReadLine();

        adj1 = adj1.Trim() + " ";
        adj2 = adj2.Trim() + " ";

        strTarget = strTarget.Insert(strTarget.IndexOf(animal1), adj1);
        strTarget = strTarget.Insert(strTarget.IndexOf(animal2), adj2);

        Console.WriteLine("{0}The final string is:{0}{1}",
                          Environment.NewLine, strTarget);
    }
}
// Output from the example might appear as follows:
//       The original string is:
//       The fox jumps over the dog.
//
//       Enter an adjective (or group of adjectives) to describe the fox: ==> bold
//       Enter an adjective (or group of adjectives) to describe the dog: ==> lazy
//
//       The final string is:
//       The bold fox jumps over the lazy dog.

open System

let animal1 = "fox"
let animal2 = "dog"

let strTarget = String.Format("The {0} jumps over the {1}.", animal1, animal2)

do
    printfn $"The original string is:{Environment.NewLine}{strTarget}{Environment.NewLine}"

    printf $"Enter an adjective (or group of adjectives) to describe the {animal1}: => "
    let adj1 = stdin.ReadLine()

    printf $"Enter an adjective (or group of adjectives) to describe the {animal2}: => "
    let adj2 = stdin.ReadLine()

    let adj1 = adj1.Trim() + " "
    let adj2 = adj2.Trim() + " "

    let strTarget = strTarget.Insert(strTarget.IndexOf animal1, adj1)
    let strTarget = strTarget.Insert(strTarget.IndexOf animal2, adj2)

    printfn $"{Environment.NewLine}The final string is:{strTarget}{Environment.NewLine}"
// Output from the example might appear as follows:
//       The original string is:
//       The fox jumps over the dog.
//
//       Enter an adjective (or group of adjectives) to describe the fox: => bold
//       Enter an adjective (or group of adjectives) to describe the dog: => lazy
//
//       The final string is:
//       The bold fox jumps over the lazy dog.

Public Class Example
    Public Shared Sub Main()
        Dim animal1 As String = "fox"
        Dim animal2 As String = "dog"
        Dim strTarget As String = String.Format("The {0} jumps over the {1}.", 
                                                animal1, animal2)
        
        Console.WriteLine("The original string is: {0}{1}{0}", 
                          Environment.NewLine, strTarget)
        
        Console.Write("Enter an adjective (or group of adjectives) " +
                      "to describe the {0}: ==> ", animal1)
        Dim adj1 As String = Console.ReadLine()
        
        Console.Write("Enter an adjective (or group of adjectives) " + 
                      "to describe the {0}: ==> ", animal2)
        Dim adj2 As String = Console.ReadLine()
        
        adj1 = adj1.Trim() + " "
        adj2 = adj2.Trim() + " "
        
        strTarget = strTarget.Insert(strTarget.IndexOf(animal1), adj1)
        strTarget = strTarget.Insert(strTarget.IndexOf(animal2), adj2)
        
        Console.WriteLine("{0}The final string is:{0}{1}", 
                          Environment.NewLine, strTarget)
    End Sub 
End Class 
' Output from the example might appear as follows:
'       The original string is:
'       The fox jumps over the dog.
'       
'       Enter an adjective (or group of adjectives) to describe the fox: ==> bold
'       Enter an adjective (or group of adjectives) to describe the dog: ==> lazy
'       
'       The final string is:
'       The bold fox jumps over the lazy dog.

Kommentarer

Indexnumreringen börjar från noll.

Den här metoden utför en ordsökning (skiftlägeskänslig och kulturkänslig) med hjälp av den aktuella kulturen. Sökningen börjar vid den första teckenpositionen för den här instansen och fortsätter till den sista teckenpositionen.

Teckenuppsättningar innehåller ignorerbara tecken, som är tecken som inte beaktas när man utför en språklig eller kulturspecifik jämförelse. I en kulturkänslig sökning, om value innehåller ett okunnigt tecken, motsvarar resultatet att söka med det tecknet borttaget. Om value endast består av ett eller flera okunniga tecken IndexOf(String) returnerar metoden alltid 0 (noll) för att indikera att matchningen hittas i början av den aktuella instansen. I följande exempel IndexOf(String) används metoden för att hitta tre understrängar (ett mjukt bindestreck (U+00AD), ett mjukt bindestreck följt av "n" och ett mjukt bindestreck följt av "m") i två strängar. Endast en av strängarna innehåller ett mjukt bindestreck. Om exemplet körs på .NET Framework 4 eller senare, i varje fall, eftersom det mjuka bindestrecket är ett okunnigt tecken, blir resultatet detsamma som om det mjuka bindestrecket inte hade inkluderats i value. När du söker efter ett mjukt bindestreck returnerar metoden 0 (noll) för att indikera att den har hittat en matchning i början av strängen.

using System;

public class Example
{
    public static void Main()
    {
        string s1 = "ani\u00ADmal";
        string s2 = "animal";
      
        // Find the index of the soft hyphen.
        Console.WriteLine(s1.IndexOf("\u00AD"));
        Console.WriteLine(s2.IndexOf("\u00AD"));
      
        // Find the index of the soft hyphen followed by "n".
        Console.WriteLine(s1.IndexOf("\u00ADn"));
        Console.WriteLine(s2.IndexOf("\u00ADn"));
      
        // Find the index of the soft hyphen followed by "m".
        Console.WriteLine(s1.IndexOf("\u00ADm"));
        Console.WriteLine(s2.IndexOf("\u00ADm"));

        // The example displays the following output
        // if run under the .NET Framework 4 or later:
        //       0
        //       0
        //       1
        //       1
        //       4
        //       3
    }
}

let s1 = "ani\u00ADmal"
let s2 = "animal"

// Find the index of the soft hyphen.
printfn $"""{s1.IndexOf "\u00AD"}"""
printfn $"""{s2.IndexOf "\u00AD"}"""

// Find the index of the soft hyphen followed by "n".
printfn $"""{s1.IndexOf "\u00ADn"}"""
printfn $"""{s2.IndexOf "\u00ADn"}"""

// Find the index of the soft hyphen followed by "m".
printfn $"""{s1.IndexOf "\u00ADm"}"""
printfn $"""{s2.IndexOf "\u00ADm"}"""

// The example displays the following output
// if run under the .NET Framework 4 or later:
//       0
//       0
//       1
//       1
//       4
//       3

Module Example
   Public Sub Main()
      Dim softHyphen As String = ChrW(&h00AD)
      Dim s1 As String = "ani" + softHyphen + "mal"
      Dim s2 As String = "animal"
      
      ' Find the index of the soft hyphen.
      Console.WriteLine(s1.IndexOf(softHyphen))
      Console.WriteLine(s2.IndexOf(softHyphen))
      
      ' Find the index of the soft hyphen followed by "n".
      Console.WriteLine(s1.IndexOf(softHyphen + "n"))
      Console.WriteLine(s2.IndexOf(softHyphen + "n"))
      
      ' Find the index of the soft hyphen followed by "m".
      Console.WriteLine(s1.IndexOf(softHyphen + "m"))
      Console.WriteLine(s2.IndexOf(softHyphen + "m"))
   End Sub
End Module
' The example displays the following output 
' if run under the .NET Framework 4 or later:
'       0
'       0
'       1
'       1
'       4
'       3

Anteckningar till anropare

Som beskrivs i Metodtips för att använda strängar rekommenderar vi att du undviker att anropa strängjämförelsemetoder som ersätter standardvärden och i stället anropar metoder som kräver att parametrar uttryckligen anges. Om du vill hitta det första indexet för en delsträng i en stränginstans med hjälp av jämförelsereglerna för den aktuella kulturen, signalerar du uttryckligen avsikten IndexOf(String, StringComparison) genom att anropa metodens överlagring med värdet CurrentCulture för för parametern comparisonType . Om du inte behöver en språkmedveten jämförelse bör du överväga att använda Ordinal.

Se även

• Int32
• CultureInfo
• IndexOfAny(Char[])
• LastIndexOf(Char)
• LastIndexOfAny(Char[])

public:
 int IndexOf(System::String ^ value, int startIndex);

public int IndexOf(string value, int startIndex);

member this.IndexOf : string * int -> int

Public Function IndexOf (value As String, startIndex As Integer) As Integer

Parametrar

Returer

Den nollbaserade indexpositionen value för från början av den aktuella instansen om strängen hittas eller -1 om den inte är det. Om value är Emptyär startIndexreturvärdet .

Undantag

Exempel

Följande exempel söker efter alla förekomster av en angiven sträng i en målsträng.

using System;

public class IndexOfTest {
    public static void Main() {

        string strSource = "This is the string which we will perform the search on";

        Console.WriteLine("The search string is:{0}\"{1}\"{0}", Environment.NewLine, strSource);

        string strTarget = "";
        int found = 0;
        int totFinds = 0;

        do {
            Console.Write("Please enter a search value to look for in the above string (hit Enter to exit) ==> ");

            strTarget = Console.ReadLine();

            if (strTarget != "") {

                for (int i = 0; i < strSource.Length; i++) {

                    found = strSource.IndexOf(strTarget, i);

                    if (found >= 0) {
                        totFinds++;
                        i = found;
                    }
                    else
                    {
                        break;
                    }
                }
            }
            else
            {
                return;
            }

            Console.WriteLine("{0}The search parameter '{1}' was found {2} times.{0}",
                    Environment.NewLine, strTarget, totFinds);

            totFinds = 0;
        } while ( true );
    }
}

open System

let strSource = "This is the string which we will perform the search on"

printfn $"The search string is:{Environment.NewLine}\"{strSource}\"{Environment.NewLine}"

let mutable broken = false
while not broken do
    let mutable totFinds = 0
    printf "Please enter a search value to look for in the above string (hit Enter to exit) => "

    let strTarget = stdin.ReadLine()

    if strTarget <> "" then
        let mutable i = 0
        let mutable broken = false
        while not broken && i <= strSource.Length - 1 do
            let found = strSource.IndexOf(strTarget, i)

            if found >= 0 then
                totFinds <- totFinds + 1
                i <- found
            else
                broken <- true
            i <- i + 1
    else
        broken <- true

    printfn $"{Environment.NewLine}The search parameter '{strTarget}' was found {totFinds} times.{Environment.NewLine}"

Public Class IndexOfTest
    
    Public Shared Sub Main()
        Dim strSource As String = "This is the string which we will perform the search on"
        
        Console.WriteLine("The search string is:{0}{1}{0}", Environment.NewLine, strSource)
        Dim strTarget As String = ""
        Dim found As Integer = 0
        Dim totFinds As Integer = 0
        
        Do
            Console.Write("Please enter a search value to look for in the above string (hit Enter to exit) ==> ")
            
            strTarget = Console.ReadLine()
            If strTarget <> "" Then
                Dim i As Integer
                
                
                For i = 0 To strSource.Length - 1
                    
                    found = strSource.IndexOf(strTarget, i)
                    If found >= 0 Then
                        
                        totFinds += 1
                        i = found
                    Else
                        Exit For
                    End If
                Next i
            Else
                Return
            
            End If
            Console.WriteLine("{0}The search parameter '{1}' was found {2} times.{0}", Environment.NewLine, strTarget, totFinds)
            
            totFinds = 0
        
        Loop While True
    End Sub
End Class

Kommentarer

Indexnumreringen börjar från 0. Parametern startIndex kan variera från 0 till längden på stränginstansen. Om startIndex är lika med längden på stränginstansen returnerar metoden -1.

Den här metoden utför en ordsökning (skiftlägeskänslig och kulturkänslig) med hjälp av den aktuella kulturen. Sökningen börjar vid teckenpositionen för den här instansen startIndex och fortsätter till den sista teckenpositionen.

Teckenuppsättningar innehåller ignorerbara tecken, som är tecken som inte beaktas när man utför en språklig eller kulturspecifik jämförelse. I en kulturkänslig sökning, om value innehåller ett okunnigt tecken, motsvarar resultatet att söka med det tecknet borttaget. Om value endast består av ett eller flera okunniga tecken IndexOf(String, Int32) returnerar startIndexmetoden alltid , vilket är teckenpositionen där sökningen börjar. I följande exempel IndexOf(String, Int32) används metoden för att hitta positionen för ett mjukt bindestreck (U+00AD) följt av ett "m" i två strängar. Endast en av strängarna innehåller den delsträng som krävs. Om exemplet körs på .NET Framework 4 eller senare, i båda fallen, eftersom det mjuka bindestrecket är ett okunnigt tecken, returnerar metoden indexet "m" i strängen. Observera att när det gäller den första strängen, som innehåller det mjuka bindestrecket följt av ett "m", returnerar metoden inte indexet för det mjuka bindestrecket utan returnerar i stället indexet för "m".

using System;

public class Example
{
    public static void Main()
    {
        string searchString = "\u00ADm";
        string s1 = "ani\u00ADmal" ;
        string s2 = "animal";

        Console.WriteLine(s1.IndexOf(searchString, 2));
        Console.WriteLine(s2.IndexOf(searchString, 2));

        // The example displays the following output:
        //       4
        //       3
    }
}

let searchString = "\u00ADm"
let s1 = "ani\u00ADmal"
let s2 = "animal"

printfn $"{s1.IndexOf(searchString, 2)}"
printfn $"{s2.IndexOf(searchString, 2)}"

// The example displays the following output:
//       4
//       3

Module Example
   Public Sub Main()
      Dim searchString As String = Chrw(&h00AD) + "m"
      Dim s1 As String = "ani" + ChrW(&h00AD) + "mal"
      Dim s2 As String = "animal"

      Console.WriteLine(s1.IndexOf(searchString, 2))
      Console.WriteLine(s2.IndexOf(searchString, 2))
   End Sub
End Module
' The example displays the following output:
'       4
'       3

Anteckningar till anropare

Som beskrivs i Metodtips för att använda strängar rekommenderar vi att du undviker att anropa strängjämförelsemetoder som ersätter standardvärden och i stället anropar metoder som kräver att parametrar uttryckligen anges. Om du vill hitta det första indexet för en delsträng som inträffar efter en viss teckenposition med hjälp av jämförelsereglerna för den aktuella kulturen, signalerar du uttryckligen avsikten IndexOf(String, Int32, StringComparison) genom att anropa metodens överlagring med värdet CurrentCulture för för dess comparisonType parameter. Om du inte behöver en språkmedveten jämförelse bör du överväga att använda Ordinal.

Se även

• Int32
• CultureInfo
• IndexOfAny(Char[])
• LastIndexOf(Char)
• LastIndexOfAny(Char[])