ArrayList.RemoveAt 方法
移除 ArrayList 的指定索引处的元素。
**命名空间:**System.Collections
**程序集:**mscorlib（在 mscorlib.dll 中）
语法
声明
Public Overridable Sub RemoveAt ( _
index As Integer _
)
用法
Dim instance As ArrayList
Dim index As Integer
instance.RemoveAt(index)
public virtual void RemoveAt (
int index
)
public:
virtual void RemoveAt (
int index
)
public void RemoveAt (
int index
)
public function RemoveAt (
index : int
)
参数
- index
要移除的元素的从零开始的索引。
异常
| 异常类型 | 条件 |
|---|---|
index 小于零。 - 或 - index 等于或大于 Count。 |
|
ArrayList 为只读。 - 或 - ArrayList 具有固定大小。 |
备注
在连续元素的集合（如列表）中，已移除元素之后的元素上移以占据空出的位置。如果该集合已编制索引，则还更新已移动的元素的索引。此行为不适用于元素按概念分组到存储桶中的集合（如哈希表）。
此方法的运算复杂度为 O(n)，其中 n 是 Count。
示例
下面的代码示例演示如何移除 ArrayList 中的元素。
Imports System
Imports System.Collections
Imports Microsoft.VisualBasic
Public Class SamplesArrayList
Public Shared Sub Main()
' Creates and initializes a new ArrayList.
Dim myAL As New ArrayList()
myAL.Add("The")
myAL.Add("quick")
myAL.Add("brown")
myAL.Add("fox")
myAL.Add("jumped")
myAL.Add("over")
myAL.Add("the")
myAL.Add("lazy")
myAL.Add("dog")
' Displays the ArrayList.
Console.WriteLine("The ArrayList initially contains the following:")
PrintValues(myAL)
' Removes the element containing "lazy".
myAL.Remove("lazy")
' Displays the current state of the ArrayList.
Console.WriteLine("After removing ""lazy"":")
PrintValues(myAL)
' Removes the element at index 5.
myAL.RemoveAt(5)
' Displays the current state of the ArrayList.
Console.WriteLine("After removing the element at index 5:")
PrintValues(myAL)
' Removes three elements starting at index 4.
myAL.RemoveRange(4, 3)
' Displays the current state of the ArrayList.
Console.WriteLine("After removing three elements starting at index 4:")
PrintValues(myAL)
End Sub
Public Shared Sub PrintValues(myList As IEnumerable)
Dim obj As [Object]
For Each obj In myList
Console.Write(" {0}", obj)
Next obj
Console.WriteLine()
End Sub 'PrintValues
End Class
' This code produces the following output.
'
' The ArrayList initially contains the following:
' The quick brown fox jumped over the lazy dog
' After removing "lazy":
' The quick brown fox jumped over the dog
' After removing the element at index 5:
' The quick brown fox jumped the dog
' After removing three elements starting at index 4:
' The quick brown fox
using System;
using System.Collections;
public class SamplesArrayList {
public static void Main() {
// Creates and initializes a new ArrayList.
ArrayList myAL = new ArrayList();
myAL.Add( "The" );
myAL.Add( "quick" );
myAL.Add( "brown" );
myAL.Add( "fox" );
myAL.Add( "jumped" );
myAL.Add( "over" );
myAL.Add( "the" );
myAL.Add( "lazy" );
myAL.Add( "dog" );
// Displays the ArrayList.
Console.WriteLine( "The ArrayList initially contains the following:" );
PrintValues( myAL );
// Removes the element containing "lazy".
myAL.Remove( "lazy" );
// Displays the current state of the ArrayList.
Console.WriteLine( "After removing \"lazy\":" );
PrintValues( myAL );
// Removes the element at index 5.
myAL.RemoveAt( 5 );
// Displays the current state of the ArrayList.
Console.WriteLine( "After removing the element at index 5:" );
PrintValues( myAL );
// Removes three elements starting at index 4.
myAL.RemoveRange( 4, 3 );
// Displays the current state of the ArrayList.
Console.WriteLine( "After removing three elements starting at index 4:" );
PrintValues( myAL );
}
public static void PrintValues( IEnumerable myList ) {
foreach ( Object obj in myList )
Console.Write( " {0}", obj );
Console.WriteLine();
}
}
/*
This code produces the following output.
The ArrayList initially contains the following:
The quick brown fox jumped over the lazy dog
After removing "lazy":
The quick brown fox jumped over the dog
After removing the element at index 5:
The quick brown fox jumped the dog
After removing three elements starting at index 4:
The quick brown fox
*/
using namespace System;
using namespace System::Collections;
void PrintValues( IEnumerable^ myList );
int main()
{
// Creates and initializes a new ArrayList.
ArrayList^ myAL = gcnew ArrayList;
myAL->Add( "The" );
myAL->Add( "quick" );
myAL->Add( "brown" );
myAL->Add( "fox" );
myAL->Add( "jumped" );
myAL->Add( "over" );
myAL->Add( "the" );
myAL->Add( "lazy" );
myAL->Add( "dog" );
// Displays the ArrayList.
Console::WriteLine( "The ArrayList initially contains the following:" );
PrintValues( myAL );
// Removes the element containing "lazy".
myAL->Remove( "lazy" );
// Displays the current state of the ArrayList.
Console::WriteLine( "After removing \"lazy\":" );
PrintValues( myAL );
// Removes the element at index 5.
myAL->RemoveAt( 5 );
// Displays the current state of the ArrayList.
Console::WriteLine( "After removing the element at index 5:" );
PrintValues( myAL );
// Removes three elements starting at index 4.
myAL->RemoveRange( 4, 3 );
// Displays the current state of the ArrayList.
Console::WriteLine( "After removing three elements starting at index 4:" );
PrintValues( myAL );
}
void PrintValues( IEnumerable^ myList )
{
IEnumerator^ myEnum = myList->GetEnumerator();
while ( myEnum->MoveNext() )
{
Object^ obj = safe_cast<Object^>(myEnum->Current);
Console::Write( " {0}", obj );
}
Console::WriteLine();
}
/*
This code produces the following output.
The ArrayList initially contains the following:
The quick brown fox jumped over the lazy dog
After removing "lazy":
The quick brown fox jumped over the dog
After removing the element at index 5:
The quick brown fox jumped the dog
After removing three elements starting at index 4:
The quick brown fox
*/
import System.*;
import System.Collections.*;
public class SamplesArrayList
{
public static void main(String[] args)
{
// Creates and initializes a new ArrayList.
ArrayList myAL = new ArrayList();
myAL.Add("The");
myAL.Add("quick");
myAL.Add("brown");
myAL.Add("fox");
myAL.Add("jumped");
myAL.Add("over");
myAL.Add("the");
myAL.Add("lazy");
myAL.Add("dog");
// Displays the ArrayList.
Console.WriteLine("The ArrayList initially contains the following:");
PrintValues(myAL);
// Removes the element containing "lazy".
myAL.Remove("lazy");
// Displays the current state of the ArrayList.
Console.WriteLine("After removing \"lazy\":");
PrintValues(myAL);
// Removes the element at index 5.
myAL.RemoveAt(5);
// Displays the current state of the ArrayList.
Console.WriteLine("After removing the element at index 5:");
PrintValues(myAL);
// Removes three elements starting at index 4.
myAL.RemoveRange(4, 3);
// Displays the current state of the ArrayList.
Console.WriteLine("After removing three elements starting at index 4:");
PrintValues(myAL);
} //main
public static void PrintValues(IEnumerable myList)
{
IEnumerator objMyEnum = myList.GetEnumerator();
while (objMyEnum.MoveNext()) {
Object obj = objMyEnum.get_Current();
Console.Write(" {0}", obj);
}
Console.WriteLine();
} //PrintValues
} //SamplesArrayList
/*
This code produces the following output.
The ArrayList initially contains the following:
The quick brown fox jumped over the lazy dog
After removing "lazy":
The quick brown fox jumped over the dog
After removing the element at index 5:
The quick brown fox jumped the dog
After removing three elements starting at index 4:
The quick brown fox
*/
import System;
import System.Collections;
// Creates and initializes a new ArrayList.
var myAL : ArrayList = new ArrayList();
myAL.Add( "The" );
myAL.Add( "quick" );
myAL.Add( "brown" );
myAL.Add( "fox" );
myAL.Add( "jumped" );
myAL.Add( "over" );
myAL.Add( "the" );
myAL.Add( "lazy" );
myAL.Add( "dog" );
// Displays the ArrayList.
Console.WriteLine( "The ArrayList initially contains the following:" );
PrintValues( myAL );
// Removes the element containing "lazy".
myAL.Remove( "lazy" );
// Displays the current state of the ArrayList.
Console.WriteLine( "After removing \"lazy\":" );
PrintValues( myAL );
// Removes the element at index 5.
myAL.RemoveAt( 5 );
// Displays the current state of the ArrayList.
Console.WriteLine( "After removing the element at index 5:" );
PrintValues( myAL );
// Removes three elements starting at index 4.
myAL.RemoveRange( 4, 3 );
// Displays the current state of the ArrayList.
Console.WriteLine( "After removing three elements starting at index 4:" );
PrintValues( myAL );
function PrintValues( myList : IEnumerable ) {
var myEnumerator : System.Collections.IEnumerator = myList.GetEnumerator();
while ( myEnumerator.MoveNext() )
Console.Write( "\t{0}", myEnumerator.Current );
Console.WriteLine();
}
/*
This code produces the following output.
The ArrayList initially contains the following:
The quick brown fox jumped over the lazy dog
After removing "lazy":
The quick brown fox jumped over the dog
After removing the element at index 5:
The quick brown fox jumped the dog
After removing three elements starting at index 4:
The quick brown fox
*/
平台
Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息
.NET Framework
受以下版本支持：2.0、1.1、1.0
.NET Compact Framework
受以下版本支持：2.0、1.0
请参见
参考
ArrayList 类
ArrayList 成员
System.Collections 命名空间
Remove
RemoveRange
Add
Insert