ArrayList.Insert(Int32, Object) 方法

定义

命名空间:

System.Collections

程序集:

System.Runtime.dll

Source:

ArrayList.cs

将元素插入 ArrayList 的指定索引处。

public:
 virtual void Insert(int index, System::Object ^ value);

public virtual void Insert (int index, object? value);

abstract member Insert : int * obj -> unit
override this.Insert : int * obj -> unit

Public Overridable Sub Insert (index As Integer, value As Object)

参数

index

Int32

应插入 value 的从零开始的索引。

value

Object

要插入的 Object。 该值可以为 null。

实现

Insert(Int32, Object)

例外

ArgumentOutOfRangeException

index 小于零。

- 或 -

index 大于 Count。

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插入 到 中 ArrayList。

using namespace System;
using namespace System::Collections;
void PrintValues( IEnumerable^ myList );
int main()
{
   
   // Creates and initializes a new ArrayList using Insert instead of Add.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Insert( 0, "The" );
   myAL->Insert( 1, "fox" );
   myAL->Insert( 2, "jumps" );
   myAL->Insert( 3, "over" );
   myAL->Insert( 4, "the" );
   myAL->Insert( 5, "dog" );
   
   // Creates and initializes a new Queue.
   Queue^ myQueue = gcnew Queue;
   myQueue->Enqueue( "quick" );
   myQueue->Enqueue( "brown" );
   
   // Displays the ArrayList and the Queue.
   Console::WriteLine( "The ArrayList initially contains the following:" );
   PrintValues( myAL );
   Console::WriteLine( "The Queue initially contains the following:" );
   PrintValues( myQueue );
   
   // Copies the Queue elements to the ArrayList at index 1.
   myAL->InsertRange( 1, myQueue );
   
   // Displays the ArrayList.
   Console::WriteLine( "After adding the Queue, the ArrayList now contains:" );
   PrintValues( myAL );
   
   // Search for "dog" and add "lazy" before it.
   myAL->Insert( myAL->IndexOf( "dog" ), "lazy" );
   
   // Displays the ArrayList.
   Console::WriteLine( "After adding \"lazy\", the ArrayList now contains:" );
   PrintValues( myAL );
   
   // Add "!!!" at the end.
   myAL->Insert( myAL->Count, "!!!" );
   
   // Displays the ArrayList.
   Console::WriteLine( "After adding \"!!!\", the ArrayList now contains:" );
   PrintValues( myAL );
   
   // Inserting an element beyond Count throws an exception.
   try
   {
      myAL->Insert( myAL->Count + 1, "anystring" );
   }
   catch ( Exception^ myException ) 
   {
      Console::WriteLine( "Exception: {0}", myException );
   }

}

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   fox   jumps   over   the   dog
 The Queue initially contains the following:
    quick   brown
 After adding the Queue, the ArrayList now contains:
    The   quick   brown   fox   jumps   over   the   dog
 After adding "lazy", the ArrayList now contains:
    The   quick   brown   fox   jumps   over   the   lazy   dog
 After adding "!!!", the ArrayList now contains:
    The   quick   brown   fox   jumps   over   the   lazy   dog   !!!
 Exception: System.ArgumentOutOfRangeException: Insertion index was out of range.  Must be non-negative and less than or equal to size.
 Parameter name: index
    at System.Collections.ArrayList.Insert(Int32 index, Object value)
    at SamplesArrayList.Main()
 */

using System;
using System.Collections;
public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList using Insert instead of Add.
      ArrayList myAL = new ArrayList();
      myAL.Insert( 0, "The" );
      myAL.Insert( 1, "fox" );
      myAL.Insert( 2, "jumps" );
      myAL.Insert( 3, "over" );
      myAL.Insert( 4, "the" );
      myAL.Insert( 5, "dog" );

      // Creates and initializes a new Queue.
      Queue myQueue = new Queue();
      myQueue.Enqueue( "quick" );
      myQueue.Enqueue( "brown" );

      // Displays the ArrayList and the Queue.
      Console.WriteLine( "The ArrayList initially contains the following:" );
      PrintValues( myAL );
      Console.WriteLine( "The Queue initially contains the following:" );
      PrintValues( myQueue );

      // Copies the Queue elements to the ArrayList at index 1.
      myAL.InsertRange( 1, myQueue );

      // Displays the ArrayList.
      Console.WriteLine( "After adding the Queue, the ArrayList now contains:" );
      PrintValues( myAL );

      // Search for "dog" and add "lazy" before it.
      myAL.Insert( myAL.IndexOf( "dog" ), "lazy" );

      // Displays the ArrayList.
      Console.WriteLine( "After adding \"lazy\", the ArrayList now contains:" );
      PrintValues( myAL );

      // Add "!!!" at the end.
      myAL.Insert( myAL.Count, "!!!" );

      // Displays the ArrayList.
      Console.WriteLine( "After adding \"!!!\", the ArrayList now contains:" );
      PrintValues( myAL );

      // Inserting an element beyond Count throws an exception.
      try  {
         myAL.Insert( myAL.Count+1, "anystring" );
      } catch ( Exception myException )  {
         Console.WriteLine("Exception: " + myException.ToString());
      }
   }

   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   fox   jumps   over   the   dog
The Queue initially contains the following:
   quick   brown
After adding the Queue, the ArrayList now contains:
   The   quick   brown   fox   jumps   over   the   dog
After adding "lazy", the ArrayList now contains:
   The   quick   brown   fox   jumps   over   the   lazy   dog
After adding "!!!", the ArrayList now contains:
   The   quick   brown   fox   jumps   over   the   lazy   dog   !!!
Exception: System.ArgumentOutOfRangeException: Insertion index was out of range.  Must be non-negative and less than or equal to size.
Parameter name: index
   at System.Collections.ArrayList.Insert(int index, Object value)
   at SamplesArrayList.Main()
*/

Imports System.Collections

Public Class SamplesArrayList    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new ArrayList using Insert instead of Add.
        Dim myAL As New ArrayList()
        myAL.Insert(0, "The")
        myAL.Insert(1, "fox")
        myAL.Insert(2, "jumps")
        myAL.Insert(3, "over")
        myAL.Insert(4, "the")
        myAL.Insert(5, "dog")
        
        ' Creates and initializes a new Queue.
        Dim myQueue As New Queue()
        myQueue.Enqueue("quick")
        myQueue.Enqueue("brown")
        
        ' Displays the ArrayList and the Queue.
        Console.WriteLine("The ArrayList initially contains the following:")
        PrintValues(myAL)
        Console.WriteLine("The Queue initially contains the following:")
        PrintValues(myQueue)
        
        ' Copies the Queue elements to the ArrayList at index 1.
        myAL.InsertRange(1, myQueue)
        
        ' Displays the ArrayList.
        Console.WriteLine("After adding the Queue, the ArrayList now contains:")
        PrintValues(myAL)
        
        ' Search for "dog" and add "lazy" before it.
        myAL.Insert(myAL.IndexOf("dog"), "lazy")
        
        ' Displays the ArrayList.
        Console.WriteLine("After adding ""lazy"", the ArrayList now contains:")
        PrintValues(myAL)
        
        ' Add "!!!" at the end.
        myAL.Insert(myAL.Count, "!!!")
        
        ' Displays the ArrayList.
        Console.WriteLine("After adding ""!!!"", the ArrayList now contains:")
        PrintValues(myAL)
        
        ' Inserting an element beyond Count throws an exception.
        Try
            myAL.Insert(myAL.Count + 1, "anystring")
        Catch myException As Exception
            Console.WriteLine("Exception: " + myException.ToString())
        End Try
    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

End Class

' This code produces the following output.
' 
' The ArrayList initially contains the following:
'     The    fox    jumps    over    the    dog
' The Queue initially contains the following:
'     quick    brown
' After adding the Queue, the ArrayList now contains:
'     The    quick    brown    fox    jumps    over    the    dog
' After adding "lazy", the ArrayList now contains:
'     The    quick    brown    fox    jumps    over    the    lazy    dog
' After adding "!!!", the ArrayList now contains:
'     The    quick    brown    fox    jumps    over    the    lazy    dog    !!!
' Exception: System.ArgumentOutOfRangeException: Insertion index was out of range.  Must be non-negative and less than or equal to size.
' Parameter name: index
'    at System.Collections.ArrayList.Insert(Int32 index, Object value)
'    at SamplesArrayList.Main()

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 ArrayList 容量，并在添加新元素之前将现有元素复制到新数组。

如果 index 等于 Count， value 则 添加到 的 ArrayList末尾。

在由连续的元素组成的集合（如列表）中，插入点下面的元素将下移以容纳新的元素。 如果集合具有索引，则移动的元素的索引也将更新。 此行为不适用于元素按概念划分为不同存储桶的集合，如哈希表。

此方法是一个 O(n) 操作，其中 n 是 Count。

另请参阅

• InsertRange(Int32, ICollection)
• Add(Object)
• Remove(Object)