ArrayList.Add(Object) 方法

定义

命名空间:

System.Collections

程序集:

System.Runtime.dll

Source:

ArrayList.cs

将对象添加到 ArrayList 的结尾处。

public:
 virtual int Add(System::Object ^ value);

public virtual int Add (object? value);

abstract member Add : obj -> int
override this.Add : obj -> int

Public Overridable Function Add (value As Object) As Integer

参数

value

Object

要添加到 Object 的结尾处的 ArrayList。 该值可以为 null。

返回

Int32

已添加 value 的 ArrayList 索引。

实现

Add(Object)

例外

NotSupportedException

ArrayList 为只读。

- 或 -

ArrayList 具有固定的大小。

示例

下面的代码示例演示如何将元素添加到 ArrayList。

using namespace System;
using namespace System::Collections;
void PrintValues( IEnumerable^ myList, char mySeparator );
int main()
{
   
   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "The" );
   myAL->Add( "quick" );
   myAL->Add( "brown" );
   myAL->Add( "fox" );
   
   // Creates and initializes a new Queue.
   Queue^ myQueue = gcnew Queue;
   myQueue->Enqueue( "jumps" );
   myQueue->Enqueue( "over" );
   myQueue->Enqueue( "the" );
   myQueue->Enqueue( "lazy" );
   myQueue->Enqueue( "dog" );
   
   // Displays the ArrayList and the Queue.
   Console::WriteLine( "The ArrayList initially contains the following:" );
   PrintValues( myAL, '\t' );
   Console::WriteLine( "The Queue initially contains the following:" );
   PrintValues( myQueue, '\t' );
   
   // Copies the Queue elements to the end of the ArrayList.
   myAL->AddRange( myQueue );
   
   // Displays the ArrayList.
   Console::WriteLine( "The ArrayList now contains the following:" );
   PrintValues( myAL, '\t' );
}

void PrintValues( IEnumerable^ myList, char mySeparator )
{
   IEnumerator^ myEnum = myList->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ obj = safe_cast<Object^>(myEnum->Current);
      Console::Write( "{0}{1}", mySeparator, obj );
   }

   Console::WriteLine();
}

/* 
This code produces the following output.

The ArrayList initially contains the following:
    The    quick    brown    fox
The Queue initially contains the following:
    jumps    over    the    lazy    dog
The ArrayList now contains the following:
    The    quick    brown    fox    jumps    over    the    lazy    dog
*/

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" );

      // Creates and initializes a new Queue.
      Queue myQueue = new Queue();
      myQueue.Enqueue( "jumps" );
      myQueue.Enqueue( "over" );
      myQueue.Enqueue( "the" );
      myQueue.Enqueue( "lazy" );
      myQueue.Enqueue( "dog" );

      // Displays the ArrayList and the Queue.
      Console.WriteLine( "The ArrayList initially contains the following:" );
      PrintValues( myAL, '\t' );
      Console.WriteLine( "The Queue initially contains the following:" );
      PrintValues( myQueue, '\t' );

      // Copies the Queue elements to the end of the ArrayList.
      myAL.AddRange( myQueue );

      // Displays the ArrayList.
      Console.WriteLine( "The ArrayList now contains the following:" );
      PrintValues( myAL, '\t' );
   }

   public static void PrintValues( IEnumerable myList, char mySeparator )  {
      foreach ( Object obj in myList )
         Console.Write( "{0}{1}", mySeparator, obj );
      Console.WriteLine();
   }
}


/*
This code produces the following output.

The ArrayList initially contains the following:
    The    quick    brown    fox
The Queue initially contains the following:
    jumps    over    the    lazy    dog
The ArrayList now contains the following:
    The    quick    brown    fox    jumps    over    the    lazy    dog
*/

Imports System.Collections

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")
        
        ' Creates and initializes a new Queue.
        Dim myQueue As New Queue()
        myQueue.Enqueue("jumps")
        myQueue.Enqueue("over")
        myQueue.Enqueue("the")
        myQueue.Enqueue("lazy")
        myQueue.Enqueue("dog")
        
        ' Displays the ArrayList and the Queue.
        Console.WriteLine("The ArrayList initially contains the following:")
        PrintValues(myAL, ControlChars.Tab)
        Console.WriteLine("The Queue initially contains the following:")
        PrintValues(myQueue, ControlChars.Tab)
        
        ' Copies the Queue elements to the end of the ArrayList.
        myAL.AddRange(myQueue)
        
        ' Displays the ArrayList.
        Console.WriteLine("The ArrayList now contains the following:")
        PrintValues(myAL, ControlChars.Tab)
    End Sub

    Public Shared Sub PrintValues(myList As IEnumerable, mySeparator As Char)
        Dim obj As [Object]
        For Each obj In  myList
          Console.Write( "{0}{1}", mySeparator, obj )
        Next obj
        Console.WriteLine()
    End Sub

End Class


' This code produces the following output.
' 
' The ArrayList initially contains the following:
'     The    quick    brown    fox
' The Queue initially contains the following:
'     jumps    over    the    lazy    dog
' The ArrayList now contains the following:
'     The    quick    brown    fox    jumps    over    the    lazy    dog

注解

ArrayList 接受 null 作为有效值，并允许重复元素。

如果 Count 已等于 Capacity，则通过自动重新分配内部数组来增加 的容量 ArrayList ，并在添加新元素之前将现有元素复制到新数组。

如果 Count 小于 Capacity，则此方法为操作 O(1) 。 如果需要增加容量以适应新元素，此方法将成为操作 O(n) ，其中 n 为 Count。

另请参阅

• AddRange(ICollection)
• Insert(Int32, Object)
• Remove(Object)
• Count