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NameObjectCollectionBase.BaseRemoveAt Method

Removes the entry at the specified index of the NameObjectCollectionBase instance.

Namespace: System.Collections.Specialized
Assembly: System (in system.dll)

'Declaration
Protected Sub BaseRemoveAt ( _
	index As Integer _
)
'Usage
Dim index As Integer

Me.BaseRemoveAt(index)
protected void BaseRemoveAt (
	int index
)
protected function BaseRemoveAt (
	index : int
)
Not applicable.

Parameters

index

The zero-based index of the entry to remove.

Exception typeCondition

ArgumentOutOfRangeException

index is outside the valid range of indexes for the collection.

NotSupportedException

The collection is read-only.

In collections of contiguous elements, such as lists, the elements that follow the removed element move up to occupy the vacated spot. If the collection is indexed, the indexes of the elements that are moved are also updated. This behavior does not apply to collections where elements are conceptually grouped into buckets, such as a hash table.

This method is an O(n) operation, where n is Count.

The following code example uses BaseRemove and BaseRemoveAt to remove elements from a NameObjectCollectionBase.

Imports System
Imports System.Collections
Imports System.Collections.Specialized

Public Class MyCollection
   Inherits NameObjectCollectionBase

   Private _de As New DictionaryEntry()

   ' Gets a key-and-value pair (DictionaryEntry) using an index.
   Default Public ReadOnly Property Item(index As Integer) As DictionaryEntry
      Get
         _de.Key = Me.BaseGetKey(index)
         _de.Value = Me.BaseGet(index)
         Return _de
      End Get
   End Property

   ' Adds elements from an IDictionary into the new collection.
   Public Sub New(d As IDictionary)
      Dim de As DictionaryEntry
      For Each de In  d
         Me.BaseAdd(CType(de.Key, [String]), de.Value)
      Next de
   End Sub 'New

   ' Removes an entry with the specified key from the collection.
   Overloads Public Sub Remove(key As [String])
      Me.BaseRemove(key)
   End Sub 'Remove

   ' Removes an entry in the specified index from the collection.
   Overloads Public Sub Remove(index As Integer)
      Me.BaseRemoveAt(index)
   End Sub 'Remove

End Class 'MyCollection


Public Class SamplesNameObjectCollectionBase   

   Public Shared Sub Main()

      ' Creates and initializes a new MyCollection instance.
      Dim d = New ListDictionary()
      d.Add("red", "apple")
      d.Add("yellow", "banana")
      d.Add("green", "pear")
      Dim myCol As New MyCollection(d)
      Console.WriteLine("Initial state of the collection (Count = {0}):", myCol.Count)
      PrintKeysAndValues(myCol)

      ' Removes an element at a specific index.
      myCol.Remove(1)
      Console.WriteLine("After removing the element at index 1 (Count = {0}):", myCol.Count)
      PrintKeysAndValues(myCol)

      ' Removes an element with a specific key.
      myCol.Remove("red")
      Console.WriteLine("After removing the element with the key ""red"" (Count = {0}):", myCol.Count)
      PrintKeysAndValues(myCol)

   End Sub 'Main

   Public Shared Sub PrintKeysAndValues(myCol As MyCollection)
      Dim i As Integer
      For i = 0 To myCol.Count - 1
         Console.WriteLine("[{0}] : {1}, {2}", i, myCol(i).Key, myCol(i).Value)
      Next i
   End Sub 'PrintKeysAndValues

End Class 'SamplesNameObjectCollectionBase 


'This code produces the following output.
'
'Initial state of the collection (Count = 3):
'[0] : red, apple
'[1] : yellow, banana
'[2] : green, pear
'After removing the element at index 1 (Count = 2):
'[0] : red, apple
'[1] : green, pear
'After removing the element with the key "red" (Count = 1):
'[0] : green, pear


import System.* ;
import System.Collections.* ;
import System.Collections.Specialized.* ;

public class MyCollection extends NameObjectCollectionBase 
{
       private DictionaryEntry _de =  new DictionaryEntry();
   
    // Gets a key-and-value pair (DictionaryEntry) using an index.
    /** @property 
     */
    public DictionaryEntry get_Item(int index)
    {
        _de.set_Key(this.BaseGetKey(index));
        _de.set_Value(this.BaseGet(index));
        return _de ;
    } //get_Item
      
    // Adds elements from an IDictionary into the new collection.
    public MyCollection(IDictionary d) 
    {
        IDictionaryEnumerator objEnum = d.GetEnumerator();

        while (objEnum.MoveNext()) {
            DictionaryEntry de = (DictionaryEntry)objEnum.get_Current();
             this.BaseAdd(((String)(de.get_Key())), de.get_Value());
        }
    } //MyCollection
   
    // Removes an entry with the specified key from the collection.
    public void Remove(String key) 
    {
        this.BaseRemove(key);
    } //Remove

    // Removes an entry in the specified index from the collection.
    public void Remove(int index) 
    {
        this.BaseRemoveAt(index);
    } //Remove
} //MyCollection


public class SamplesNameObjectCollectionBase
{
    public static void main(String[] args)
    {
        // Creates and initializes a new MyCollection instance.
        IDictionary d = new ListDictionary();
        d.Add("red", "apple");
        d.Add("yellow", "banana");
        d.Add("green", "pear");
        MyCollection myCol =  new MyCollection(d);
        Console.WriteLine("Initial state of the collection (Count = {0}):",
            System.Convert.ToString(myCol.get_Count()));
        PrintKeysAndValues(myCol);
      
        // Removes an element at a specific index.
        myCol.Remove(1);
        Console.WriteLine("After removing the element at index 1"
            + " (Count = {0}):",
        System.Convert.ToString(myCol.get_Count()));
        PrintKeysAndValues(myCol);
      
        // Removes an element with a specific key.
        myCol.Remove("red");
        Console.WriteLine("After removing the element with the key \"red\""
            + " (Count = {0}):",System.Convert.ToString( myCol.get_Count()));
        PrintKeysAndValues(myCol);
    } //main
       
    public static void PrintKeysAndValues(MyCollection myCol)
    {
        for (int i=0; i < myCol.get_Count(); i++) {
            Console.WriteLine("[{0}] : {1}, {2}",System.Convert.ToString(i),
                myCol .get_Item( i).get_Key(), myCol .get_Item( i).get_Value());
        } 
    } //PrintKeysAndValues
} //SamplesNameObjectCollectionBase 

/*
This code produces the following output.

Initial state of the collection (Count = 3):
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
After removing the element at index 1 (Count = 2):
[0] : red, apple
[1] : green, pear
After removing the element with the key "red" (Count = 1):
[0] : green, pear

*/

Windows 98, Windows Server 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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0

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