ArrayList 类
使用大小可按需动态增加的数组实现 IList 接口。
**命名空间:**System.Collections
**程序集:**mscorlib（在 mscorlib.dll 中）
语法
声明
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Class ArrayList
Implements IList, ICollection, IEnumerable, ICloneable
用法
Dim instance As ArrayList
[SerializableAttribute]
[ComVisibleAttribute(true)]
public class ArrayList : IList, ICollection, IEnumerable,
ICloneable
[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class ArrayList : IList, ICollection, IEnumerable,
ICloneable
/** @attribute SerializableAttribute() */
/** @attribute ComVisibleAttribute(true) */
public class ArrayList implements IList, ICollection,
IEnumerable, ICloneable
SerializableAttribute
ComVisibleAttribute(true)
public class ArrayList implements IList, ICollection,
IEnumerable, ICloneable
备注
不保证会对 ArrayList 排序。在执行需要对 ArrayList 排序的操作（如 BinarySearch）之前，必须对 ArrayList 进行排序。
ArrayList 的容量是 ArrayList 可以保存的元素数。ArrayList 的默认初始容量为 0。随着元素添加到 ArrayList 中，容量会根据需要通过重新分配自动增加。可通过调用 TrimToSize 或通过显式设置 Capacity 属性减少容量。
使用整数索引可以访问此集合中的元素。此集合中的索引从零开始。
ArrayList 接受 空引用（在 Visual Basic 中为 Nothing） 作为有效值并且允许重复的元素。
示例
下面的代码示例演示如何创建并初始化 ArrayList 以及如何打印出其值。
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("Hello")
myAL.Add("World")
myAL.Add("!")
' Displays the properties and values of the ArrayList.
Console.WriteLine("myAL")
Console.WriteLine(" Count: {0}", myAL.Count)
Console.WriteLine(" Capacity: {0}", myAL.Capacity)
Console.Write(" Values:")
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 output similar to the following:
'
' myAL
' Count: 3
' Capacity: 4
' Values: Hello World !
using System;
using System.Collections;
public class SamplesArrayList {
public static void Main() {
// Creates and initializes a new ArrayList.
ArrayList myAL = new ArrayList();
myAL.Add("Hello");
myAL.Add("World");
myAL.Add("!");
// Displays the properties and values of the ArrayList.
Console.WriteLine( "myAL" );
Console.WriteLine( " Count: {0}", myAL.Count );
Console.WriteLine( " Capacity: {0}", myAL.Capacity );
Console.Write( " Values:" );
PrintValues( myAL );
}
public static void PrintValues( IEnumerable myList ) {
foreach ( Object obj in myList )
Console.Write( " {0}", obj );
Console.WriteLine();
}
}
/*
This code produces output similar to the following:
myAL
Count: 3
Capacity: f
Values: Hello World !
*/
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( "Hello" );
myAL->Add( "World" );
myAL->Add( "!" );
// Displays the properties and values of the ArrayList.
Console::WriteLine( "myAL" );
Console::WriteLine( " Count: {0}", myAL->Count );
Console::WriteLine( " Capacity: {0}", myAL->Capacity );
Console::Write( " Values:" );
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 output similar to the following:
myAL
Count: 3
Capacity: 4
Values: Hello World !
*/
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("Hello");
myAL.Add("World");
myAL.Add("!");
// Displays the properties and values of the ArrayList.
Console.WriteLine("myAL");
Console.WriteLine(" Count: {0}", (Int32)myAL.get_Count());
Console.WriteLine(" Capacity: {0}", (Int32)myAL.get_Capacity());
Console.Write(" Values:");
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 output similar to the following:
myAL
Count: 3
Capacity: 4
Values: Hello World !
*/
import System;
import System.Collections;
// Creates and initializes a new ArrayList.
var myAL : ArrayList = new ArrayList();
myAL.Add("Hello");
myAL.Add("World");
myAL.Add("!");
// Displays the properties and values of the ArrayList.
Console.WriteLine( "myAL" );
Console.WriteLine( "\tCount: {0}", myAL.Count );
Console.WriteLine( "\tCapacity: {0}", myAL.Capacity );
Console.Write( "\tValues:" );
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 output similar to the following:
myAL
Count: 3
Capacity: 4
Values: Hello World !
*/
继承层次结构
System.Object
System.Collections.ArrayList
System.Windows.Forms.DomainUpDown.DomainUpDownItemCollection
线程安全
此类型的公共静态（在 Visual Basic 中为 Shared）成员是线程安全的。但不能保证任何实例成员是线程安全的。
只要集合未修改，ArrayList 就可以同时支持多个阅读器。若要保证 ArrayList 的线程安全，则必须通过由 Synchronized 方法返回的包装来执行所有操作。
通过集合枚举在本质上不是一个线程安全的过程。即使一个集合已进行同步，其他线程仍可以修改该集合，这将导致枚举数引发异常。若要在枚举过程中保证线程安全，可以在整个枚举过程中锁定集合，或者捕捉由于其他线程进行的更改而引发的异常。
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 成员
System.Collections 命名空间
IList
System.Collections.Generic.List