Collection<T>.ClearItems 메서드

정의

네임스페이스:: System.Collections.ObjectModel

어셈블리:: mscorlib.dll, System.Runtime.dll

어셈블리:: mscorlib.dll

어셈블리:: System.Runtime.dll

어셈블리:: netstandard.dll

중요

일부 정보는 릴리스되기 전에 상당 부분 수정될 수 있는 시험판 제품과 관련이 있습니다. Microsoft는 여기에 제공된 정보에 대해 어떠한 명시적이거나 묵시적인 보증도 하지 않습니다.

에서 모든 요소를 Collection<T>제거합니다.

protected:
 virtual void ClearItems();

protected virtual void ClearItems();

abstract member ClearItems : unit -> unit
override this.ClearItems : unit -> unit

Protected Overridable Sub ClearItems ()

예제

다음 코드 예제에서는 제네릭 클래스의 생성 된 형식에서 컬렉션 클래스를 파생 하는 방법 및 보호 된 재정의 Collection<T> 하는 방법, ClearItems RemoveItem및 SetItem 메서드에 대 한 사용자 지정 동작을 제공 하는 , 및 Clear 메서드 및 속성 설정 Item[] 에 대 한 Insert Remove Add합니다.InsertItem

이 예제에서 제공하는 사용자 지정 동작은 Changed 보호된 각 메서드의 끝에서 발생하는 알림 이벤트입니다. Dinosaurs 클래스는 Collection<string>(Visual Basic Collection(Of String))를 상속하고 이벤트 정보에 DinosaursChangedEventArgs 클래스를 사용하는 Changed 이벤트 및 변경 종류를 식별하는 열거형을 정의합니다.

코드 예제에서는 사용자 지정 이벤트를 보여 주는 몇 가지 속성과 메서드 Collection<T> 를 호출합니다.

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;

public class Dinosaurs : Collection<string>
{
    public event EventHandler<DinosaursChangedEventArgs> Changed;

    protected override void InsertItem(int index, string newItem)
    {
        base.InsertItem(index, newItem);

        EventHandler<DinosaursChangedEventArgs> temp = Changed;
        if (temp != null)
        {
            temp(this, new DinosaursChangedEventArgs(
                ChangeType.Added, newItem, null));
        }
    }

    protected override void SetItem(int index, string newItem)
    {
        string replaced = Items[index];
        base.SetItem(index, newItem);

        EventHandler<DinosaursChangedEventArgs> temp = Changed;
        if (temp != null)
        {
            temp(this, new DinosaursChangedEventArgs(
                ChangeType.Replaced, replaced, newItem));
        }
    }

    protected override void RemoveItem(int index)
    {
        string removedItem = Items[index];
        base.RemoveItem(index);

        EventHandler<DinosaursChangedEventArgs> temp = Changed;
        if (temp != null)
        {
            temp(this, new DinosaursChangedEventArgs(
                ChangeType.Removed, removedItem, null));
        }
    }

    protected override void ClearItems()
    {
        base.ClearItems();

        EventHandler<DinosaursChangedEventArgs> temp = Changed;
        if (temp != null)
        {
            temp(this, new DinosaursChangedEventArgs(
                ChangeType.Cleared, null, null));
        }
    }
}

// Event argument for the Changed event.
//
public class DinosaursChangedEventArgs : EventArgs
{
    public readonly string ChangedItem;
    public readonly ChangeType ChangeType;
    public readonly string ReplacedWith;

    public DinosaursChangedEventArgs(ChangeType change, string item,
        string replacement)
    {
        ChangeType = change;
        ChangedItem = item;
        ReplacedWith = replacement;
    }
}

public enum ChangeType
{
    Added,
    Removed,
    Replaced,
    Cleared
};

public class Demo
{
    public static void Main()
    {
        Dinosaurs dinosaurs = new Dinosaurs();

        dinosaurs.Changed += ChangedHandler;

        dinosaurs.Add("Psitticosaurus");
        dinosaurs.Add("Caudipteryx");
        dinosaurs.Add("Compsognathus");
        dinosaurs.Add("Muttaburrasaurus");

        Display(dinosaurs);

        Console.WriteLine("\nIndexOf(\"Muttaburrasaurus\"): {0}",
            dinosaurs.IndexOf("Muttaburrasaurus"));

        Console.WriteLine("\nContains(\"Caudipteryx\"): {0}",
            dinosaurs.Contains("Caudipteryx"));

        Console.WriteLine("\nInsert(2, \"Nanotyrannus\")");
        dinosaurs.Insert(2, "Nanotyrannus");

        Console.WriteLine("\ndinosaurs[2]: {0}", dinosaurs[2]);

        Console.WriteLine("\ndinosaurs[2] = \"Microraptor\"");
        dinosaurs[2] = "Microraptor";

        Console.WriteLine("\nRemove(\"Microraptor\")");
        dinosaurs.Remove("Microraptor");

        Console.WriteLine("\nRemoveAt(0)");
        dinosaurs.RemoveAt(0);

        Display(dinosaurs);
    }

    private static void Display(Collection<string> cs)
    {
        Console.WriteLine();
        foreach( string item in cs )
        {
            Console.WriteLine(item);
        }
    }

    private static void ChangedHandler(object source,
        DinosaursChangedEventArgs e)
    {

        if (e.ChangeType==ChangeType.Replaced)
        {
            Console.WriteLine("{0} was replaced with {1}", e.ChangedItem,
                e.ReplacedWith);
        }
        else if(e.ChangeType==ChangeType.Cleared)
        {
            Console.WriteLine("The dinosaur list was cleared.");
        }
        else
        {
            Console.WriteLine("{0} was {1}.", e.ChangedItem, e.ChangeType);
        }
    }
}

/* This code example produces the following output:

Psitticosaurus was Added.
Caudipteryx was Added.
Compsognathus was Added.
Muttaburrasaurus was Added.

Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus

IndexOf("Muttaburrasaurus"): 3

Contains("Caudipteryx"): True

Insert(2, "Nanotyrannus")
Nanotyrannus was Added.

dinosaurs[2]: Nanotyrannus

dinosaurs[2] = "Microraptor"
Nanotyrannus was replaced with Microraptor

Remove("Microraptor")
Microraptor was Removed.

RemoveAt(0)
Psitticosaurus was Removed.

Caudipteryx
Compsognathus
Muttaburrasaurus
 */

Imports System.Collections.Generic
Imports System.Collections.ObjectModel

Public Class Dinosaurs
    Inherits Collection(Of String)

    Public Event Changed As EventHandler(Of DinosaursChangedEventArgs)

    Protected Overrides Sub InsertItem( _
        ByVal index As Integer, ByVal newItem As String)

        MyBase.InsertItem(index, newItem)

        RaiseEvent Changed(Me, New DinosaursChangedEventArgs( _
            ChangeType.Added, newItem, Nothing))
    End Sub

    Protected Overrides Sub SetItem(ByVal index As Integer, _
        ByVal newItem As String)

        Dim replaced As String = Items(index)
        MyBase.SetItem(index, newItem)

        RaiseEvent Changed(Me, New DinosaursChangedEventArgs( _
            ChangeType.Replaced, replaced, newItem))
    End Sub

    Protected Overrides Sub RemoveItem(ByVal index As Integer)

        Dim removedItem As String = Items(index)
        MyBase.RemoveItem(index)

        RaiseEvent Changed(Me, New DinosaursChangedEventArgs( _
            ChangeType.Removed, removedItem, Nothing))
    End Sub

    Protected Overrides Sub ClearItems()
        MyBase.ClearItems()

        RaiseEvent Changed(Me, New DinosaursChangedEventArgs( _
            ChangeType.Cleared, Nothing, Nothing))
    End Sub

End Class

' Event argument for the Changed event.
'
Public Class DinosaursChangedEventArgs
    Inherits EventArgs

    Public ReadOnly ChangedItem As String
    Public ReadOnly ChangeType As ChangeType
    Public ReadOnly ReplacedWith As String

    Public Sub New(ByVal change As ChangeType, ByVal item As String, _
        ByVal replacement As String)

        ChangeType = change
        ChangedItem = item
        ReplacedWith = replacement
    End Sub
End Class

Public Enum ChangeType
    Added
    Removed
    Replaced
    Cleared
End Enum

Public Class Demo
    
    Public Shared Sub Main() 

        Dim dinosaurs As New Dinosaurs

        AddHandler dinosaurs.Changed, AddressOf ChangedHandler

        dinosaurs.Add("Psitticosaurus")
        dinosaurs.Add("Caudipteryx")
        dinosaurs.Add("Compsognathus")
        dinosaurs.Add("Muttaburrasaurus")

        Display(dinosaurs)
    
        Console.WriteLine(vbLf & "IndexOf(""Muttaburrasaurus""): {0}", _
            dinosaurs.IndexOf("Muttaburrasaurus"))

        Console.WriteLine(vbLf & "Contains(""Caudipteryx""): {0}", _
            dinosaurs.Contains("Caudipteryx"))

        Console.WriteLine(vbLf & "Insert(2, ""Nanotyrannus"")")
        dinosaurs.Insert(2, "Nanotyrannus")

        Console.WriteLine(vbLf & "dinosaurs(2): {0}", dinosaurs(2))

        Console.WriteLine(vbLf & "dinosaurs(2) = ""Microraptor""")
        dinosaurs(2) = "Microraptor"

        Console.WriteLine(vbLf & "Remove(""Microraptor"")")
        dinosaurs.Remove("Microraptor")

        Console.WriteLine(vbLf & "RemoveAt(0)")
        dinosaurs.RemoveAt(0)

        Display(dinosaurs)
 
    End Sub
    
    Private Shared Sub Display(ByVal cs As Collection(Of String)) 
        Console.WriteLine()
        For Each item As String In cs
            Console.WriteLine(item)
        Next item
    End Sub

    Private Shared Sub ChangedHandler(ByVal source As Object, _
        ByVal e As DinosaursChangedEventArgs)

        If e.ChangeType = ChangeType.Replaced Then
            Console.WriteLine("{0} was replaced with {1}", _
                e.ChangedItem, e.ReplacedWith)

        ElseIf e.ChangeType = ChangeType.Cleared Then
            Console.WriteLine("The dinosaur list was cleared.")

        Else
            Console.WriteLine("{0} was {1}.", _
                e.ChangedItem, e.ChangeType)
        End If
    End Sub

End Class

' This code example produces the following output:
'
'Psitticosaurus was Added.
'Caudipteryx was Added.
'Compsognathus was Added.
'Muttaburrasaurus was Added.
'
'Psitticosaurus
'Caudipteryx
'Compsognathus
'Muttaburrasaurus
'
'IndexOf("Muttaburrasaurus"): 3
'
'Contains("Caudipteryx"): True
'
'Insert(2, "Nanotyrannus")
'Nanotyrannus was Added.
'
'dinosaurs(2): Nanotyrannus
'
'dinosaurs(2) = "Microraptor"
'Nanotyrannus was replaced with Microraptor
'
'Remove("Microraptor")
'Microraptor was Removed.
'
'RemoveAt(0)
'Psitticosaurus was Removed.
'
'Caudipteryx
'Compsognathus
'Muttaburrasaurus

설명

Count 가 0으로 설정되고 컬렉션 요소의 다른 개체에 대한 참조도 해제됩니다.

이 메서드는 O(n) 연산입니다. 여기서 n 는 Count.

상속자 참고

파생 클래스는 메서드의 동작을 변경 하려면이 메서드를 재정의할 Clear() 수 있습니다.

적용 대상

추가 정보

Clear()

피드백

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