ArrayList.Insert(Int32, Object) Methode

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)

Parameters

Implementeringen

Uitzonderingen

Voorbeelden

In het volgende codevoorbeeld ziet u hoe u elementen invoegt in de ArrayList.

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()

Opmerkingen

ArrayList null accepteert als een geldige waarde en staat dubbele elementen toe.

Als Count deze al gelijk is Capacityaan, wordt de capaciteit van de ArrayList matrix verhoogd door de interne matrix automatisch opnieuw te verplaatsen en worden de bestaande elementen gekopieerd naar de nieuwe matrix voordat het nieuwe element wordt toegevoegd.

Als index dit gelijk is aan Count, value wordt toegevoegd aan het einde van ArrayList.

In verzamelingen van aaneengesloten elementen, zoals lijsten, gaan de elementen die volgen op de invoegpositie omlaag om het nieuwe element weer te geven. Als de verzameling is geïndexeerd, worden de indexen van de verplaatste elementen ook bijgewerkt. Dit gedrag is niet van toepassing op verzamelingen waarin elementen conceptueel zijn gegroepeerd in buckets, zoals een hash-tabel.

Deze methode is een O(n) bewerking, waarbij n .Count

Zie ook

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