NameObjectCollectionBase.BaseRemove(String) 方法
定义
重要
一些信息与预发行产品相关,相应产品在发行之前可能会进行重大修改。 对于此处提供的信息,Microsoft 不作任何明示或暗示的担保。
从实例中删除具有指定键的 NameObjectCollectionBase 条目。
protected:
void BaseRemove(System::String ^ name);
protected void BaseRemove(string name);
member this.BaseRemove : string -> unit
Protected Sub BaseRemove (name As String)
参数
例外
集合为只读。
示例
下面的代码示例使用 BaseRemove 和 BaseRemoveAt 删除元素 NameObjectCollectionBase。
using System;
using System.Collections;
using System.Collections.Specialized;
public class MyCollection : NameObjectCollectionBase {
private DictionaryEntry _de = new DictionaryEntry();
// Gets a key-and-value pair (DictionaryEntry) using an index.
public DictionaryEntry this[ int index ] {
get {
_de.Key = this.BaseGetKey( index );
_de.Value = this.BaseGet( index );
return( _de );
}
}
// Adds elements from an IDictionary into the new collection.
public MyCollection( IDictionary d ) {
foreach ( DictionaryEntry de in d ) {
this.BaseAdd( (String) de.Key, de.Value );
}
}
// Removes an entry with the specified key from the collection.
public void Remove( String key ) {
this.BaseRemove( key );
}
// Removes an entry in the specified index from the collection.
public void Remove( int index ) {
this.BaseRemoveAt( index );
}
}
public class SamplesNameObjectCollectionBase {
public static void Main() {
// Creates and initializes a new MyCollection instance.
IDictionary d = new ListDictionary();
d.Add( "red", "apple" );
d.Add( "yellow", "banana" );
d.Add( "green", "pear" );
MyCollection myCol = new MyCollection( d );
Console.WriteLine( "Initial state of the collection (Count = {0}):", myCol.Count );
PrintKeysAndValues( myCol );
// Removes an element at a specific index.
myCol.Remove( 1 );
Console.WriteLine( "After removing the element at index 1 (Count = {0}):", myCol.Count );
PrintKeysAndValues( myCol );
// Removes an element with a specific key.
myCol.Remove( "red" );
Console.WriteLine( "After removing the element with the key \"red\" (Count = {0}):", myCol.Count );
PrintKeysAndValues( myCol );
}
public static void PrintKeysAndValues( MyCollection myCol ) {
for ( int i = 0; i < myCol.Count; i++ ) {
Console.WriteLine( "[{0}] : {1}, {2}", i, myCol[i].Key, myCol[i].Value );
}
}
}
/*
This code produces the following output.
Initial state of the collection (Count = 3):
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
After removing the element at index 1 (Count = 2):
[0] : red, apple
[1] : green, pear
After removing the element with the key "red" (Count = 1):
[0] : green, pear
*/
Imports System.Collections
Imports System.Collections.Specialized
Public Class MyCollection
Inherits NameObjectCollectionBase
Private _de As New DictionaryEntry()
' Gets a key-and-value pair (DictionaryEntry) using an index.
Default Public ReadOnly Property Item(index As Integer) As DictionaryEntry
Get
_de.Key = Me.BaseGetKey(index)
_de.Value = Me.BaseGet(index)
Return _de
End Get
End Property
' Adds elements from an IDictionary into the new collection.
Public Sub New(d As IDictionary)
Dim de As DictionaryEntry
For Each de In d
Me.BaseAdd(CType(de.Key, [String]), de.Value)
Next de
End Sub
' Removes an entry with the specified key from the collection.
Overloads Public Sub Remove(key As [String])
Me.BaseRemove(key)
End Sub
' Removes an entry in the specified index from the collection.
Overloads Public Sub Remove(index As Integer)
Me.BaseRemoveAt(index)
End Sub
End Class
Public Class SamplesNameObjectCollectionBase
Public Shared Sub Main()
' Creates and initializes a new MyCollection instance.
Dim d = New ListDictionary()
d.Add("red", "apple")
d.Add("yellow", "banana")
d.Add("green", "pear")
Dim myCol As New MyCollection(d)
Console.WriteLine("Initial state of the collection (Count = {0}):", myCol.Count)
PrintKeysAndValues(myCol)
' Removes an element at a specific index.
myCol.Remove(1)
Console.WriteLine("After removing the element at index 1 (Count = {0}):", myCol.Count)
PrintKeysAndValues(myCol)
' Removes an element with a specific key.
myCol.Remove("red")
Console.WriteLine("After removing the element with the key ""red"" (Count = {0}):", myCol.Count)
PrintKeysAndValues(myCol)
End Sub
Public Shared Sub PrintKeysAndValues(myCol As MyCollection)
Dim i As Integer
For i = 0 To myCol.Count - 1
Console.WriteLine("[{0}] : {1}, {2}", i, myCol(i).Key, myCol(i).Value)
Next i
End Sub
End Class
'This code produces the following output.
'
'Initial state of the collection (Count = 3):
'[0] : red, apple
'[1] : yellow, banana
'[2] : green, pear
'After removing the element at index 1 (Count = 2):
'[0] : red, apple
'[1] : green, pear
'After removing the element with the key "red" (Count = 1):
'[0] : green, pear
注解
NameObjectCollectionBase如果不包含具有指定键的元素,则NameObjectCollectionBase保持不变。 不会引发异常。
在连续元素(如列表)的集合中,已删除元素后面的元素向上移动以占据空置的位置。 如果为集合编制索引,则移动的元素的索引也会更新。 此行为不适用于在概念上将元素分组到存储桶中的集合,例如哈希表。
此方法是 O(n) 操作,其中 n 。Count