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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)

protected:
void BaseRemoveAt (
	int 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.

#using <System.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;

public ref class MyCollection : public NameObjectCollectionBase  {

private:
   DictionaryEntry^ _de;

   // Gets a key-and-value pair (DictionaryEntry) using an index.
public:
   property DictionaryEntry^ default[ int ]  {
      DictionaryEntry^ get(int index)  {
         _de->Key = this->BaseGetKey( index );
         _de->Value = this->BaseGet( index );
         return( _de );
      }
   }

   // Adds elements from an IDictionary into the new collection.
   MyCollection( IDictionary^ d )  {

      _de = gcnew DictionaryEntry();

      for each ( DictionaryEntry^ de in d )  {
         this->BaseAdd( (String^) de->Key, de->Value );
      }
   }

   // Removes an entry with the specified key from the collection.
   void Remove( String^ key )  {
      this->BaseRemove( key );
   }

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

public ref class SamplesNameObjectCollectionBase  {

public:
   static void Main()  {

      // Creates and initializes a new MyCollection instance.
      IDictionary^ d = gcnew ListDictionary();
      d->Add( "red", "apple" );
      d->Add( "yellow", "banana" );
      d->Add( "green", "pear" );
      MyCollection^ myCol = gcnew 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 );

   }

   static void PrintKeysAndValues( MyCollection^ myCol )  {
      for ( int i = 0; i < myCol->Count; i++ )  {
         Console::WriteLine( "[{0}] : {1}, {2}", i, myCol[i]->Key, myCol[i]->Value );
      }
   }
};

int main()
{
    SamplesNameObjectCollectionBase::Main();
}

/*
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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