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NameObjectCollectionBase.BaseClear Method

Removes all entries from the NameObjectCollectionBase instance.

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

'Declaration
Protected Sub BaseClear
'Usage

Me.BaseClear
protected void BaseClear ()
protected function BaseClear ()
Not applicable.

Exception typeCondition

NotSupportedException

The collection is read-only.

Count is set to zero, and references to other objects from elements of the collection are also released.

This method is an O(1) operation.

The following code example uses BaseClear to remove all 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

   ' Clears all the elements in the collection.
   Public Sub Clear()
      Me.BaseClear()
   End Sub 'Clear

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 all elements from the collection.
      myCol.Clear()
      Console.WriteLine("After clearing the collection (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 clearing the collection (Count = 0):


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

    // Clears all the elements in the collection.
    public void Clear() 
    {
        this.BaseClear();
    } //Clear
} //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 all elements from the collection.
        myCol.Clear();
        Console.WriteLine("After clearing the collection (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 clearing the collection (Count = 0):

*/

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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