Hashtable.Clear-Methode

Entfernt alle Elemente aus der Hashtable.

Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Overridable Sub Clear
'Usage
Dim instance As Hashtable

instance.Clear

public virtual void Clear ()

public:
virtual void Clear ()

public void Clear ()

public function Clear ()

Ausnahmen

Ausnahmetyp	Bedingung
NotSupportedException	Die Hashtable ist schreibgeschützt.

Hinweise

Count wird auf 0 (null) festgelegt, und Verweise auf andere Objekte von Elementen in der Auflistung werden ebenfalls freigegeben. Die Kapazität bleibt unverändert.

Diese Methode ist eine O(n)-Operation, wobei n gleich Count ist.

Beispiel

Im folgenden Beispiel wird das Löschen der Werte der Hashtable erläutert.

Imports System
Imports System.Collections

Public Class SamplesHashtable

    Public Shared Sub Main()

        ' Creates and initializes a new Hashtable.
        Dim myHT As New Hashtable()
        myHT.Add("one", "The")
        myHT.Add("two", "quick")
        myHT.Add("three", "brown")
        myHT.Add("four", "fox")
        myHT.Add("five", "jumped")

        ' Displays the count and values of the Hashtable.
        Console.WriteLine("Initially,")
        Console.WriteLine("   Count    : {0}", myHT.Count)
        Console.WriteLine("   Values:")
        PrintKeysAndValues(myHT)

        ' Clears the Hashtable.
        myHT.Clear()

        ' Displays the count and values of the Hashtable.
        Console.WriteLine("After Clear,")
        Console.WriteLine("   Count    : {0}", myHT.Count)
        Console.WriteLine("   Values:")
        PrintKeysAndValues(myHT)

    End Sub 'Main


    Public Shared Sub PrintKeysAndValues(myHT As Hashtable)
        Console.WriteLine(vbTab + "-KEY-" + vbTab + "-VALUE-")
        Dim de As DictionaryEntry
        For Each de In  myHT
            Console.WriteLine(vbTab + "{0}:" + vbTab + "{1}", de.Key, de.Value)
        Next de
        Console.WriteLine()
    End Sub 'PrintKeysAndValues

End Class 'SamplesHashtable 


' This code produces the following output.
' 
' Initially,
'    Count    : 5
'    Values:
'         -KEY-   -VALUE-
'         two:    quick
'         three:  brown
'         four:   fox
'         five:   jumped
'         one:    The
'
' After Clear,
'    Count    : 0
'    Values:
'         -KEY-   -VALUE-
'

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

   public static void Main()  {

      // Creates and initializes a new Hashtable.
      Hashtable myHT = new Hashtable();
      myHT.Add( "one", "The" );
      myHT.Add( "two", "quick" );
      myHT.Add( "three", "brown" );
      myHT.Add( "four", "fox" );
      myHT.Add( "five", "jumped" );

      // Displays the count and values of the Hashtable.
      Console.WriteLine( "Initially," );
      Console.WriteLine( "   Count    : {0}", myHT.Count );
      Console.WriteLine( "   Values:" );
      PrintKeysAndValues( myHT );

      // Clears the Hashtable.
      myHT.Clear();

      // Displays the count and values of the Hashtable.
      Console.WriteLine( "After Clear," );
      Console.WriteLine( "   Count    : {0}", myHT.Count );
      Console.WriteLine( "   Values:" );
      PrintKeysAndValues( myHT );
   }


   public static void PrintKeysAndValues( Hashtable myHT )  {
      Console.WriteLine( "\t-KEY-\t-VALUE-" );
      foreach ( DictionaryEntry de in myHT )
         Console.WriteLine( "\t{0}:\t{1}", de.Key, de.Value );
      Console.WriteLine();
   }

}


/* 
This code produces the following output.

Initially,
   Count    : 5
   Values:
        -KEY-   -VALUE-
        two:    quick
        three:  brown
        four:   fox
        five:   jumped
        one:    The

After Clear,
   Count    : 0
   Values:
        -KEY-   -VALUE-

*/ 

using namespace System;
using namespace System::Collections;
void PrintKeysAndValues( Hashtable^ myHT );
int main()
{
   
   // Creates and initializes a new Hashtable.
   Hashtable^ myHT = gcnew Hashtable;
   myHT->Add( "one", "The" );
   myHT->Add( "two", "quick" );
   myHT->Add( "three", "brown" );
   myHT->Add( "four", "fox" );
   myHT->Add( "five", "jumped" );
   
   // Displays the count and values of the Hashtable.
   Console::WriteLine( "Initially," );
   Console::WriteLine( "   Count    : {0}", myHT->Count );
   Console::WriteLine( "   Values:" );
   PrintKeysAndValues( myHT );
   
   // Clears the Hashtable.
   myHT->Clear();
   
   // Displays the count and values of the Hashtable.
   Console::WriteLine( "After Clear," );
   Console::WriteLine( "   Count    : {0}", myHT->Count );
   Console::WriteLine( "   Values:" );
   PrintKeysAndValues( myHT );
}

void PrintKeysAndValues( Hashtable^ myHT )
{
   Console::WriteLine( "\t-KEY-\t-VALUE-" );
   IEnumerator^ myEnum = myHT->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      DictionaryEntry de = *safe_cast<DictionaryEntry ^>(myEnum->Current);
      Console::WriteLine( "\t{0}:\t{1}", de.Key, de.Value );
   }

   Console::WriteLine();
}

/* 
 This code produces the following output.
 
 Initially,
    Count    : 5
    Values:
         -KEY-   -VALUE-
         two:    quick
         three:  brown
         four:   fox
         five:   jumped
         one:    The

 After Clear,
    Count    : 0
    Values:
         -KEY-   -VALUE-

 */

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

public class SamplesHashtable
{
    public static void main(String[] args)
    {
        // Creates and initializes a new Hashtable.
        Hashtable myHT = new Hashtable();

        myHT.Add("one", "The");
        myHT.Add("two", "quick");
        myHT.Add("three", "brown");
        myHT.Add("four", "fox");
        myHT.Add("five", "jumped");

        // Displays the count and values of the Hashtable.
        Console.WriteLine("Initially,");
        Console.WriteLine("   Count    : {0}", 
            System.Convert.ToString(myHT.get_Count()));
        Console.WriteLine("   Values:");
        PrintKeysAndValues(myHT);

        // Clears the Hashtable.
        myHT.Clear();

        // Displays the count and values of the Hashtable.
        Console.WriteLine("After Clear,");
        Console.WriteLine("   Count    : {0}", 
            System.Convert.ToString(myHT.get_Count()));
        Console.WriteLine("   Values:");
        PrintKeysAndValues(myHT);
    } //main

    public static void PrintKeysAndValues(Hashtable myHT)
    {
        Console.WriteLine("\t-KEY-\t-VALUE-");
        IEnumerator myEnumerator = myHT.GetEnumerator();

        while (myEnumerator.MoveNext()) {
            DictionaryEntry de = (DictionaryEntry)myEnumerator.get_Current();
            Console.WriteLine("\t{0}:\t{1}", de.get_Key(), de.get_Value());
        }
        Console.WriteLine();
    } //PrintKeysAndValues
} //SamplesHashtable 

/* 
 This code produces the following output.
 
 Initially,
    Count    : 5
    Values:
         -KEY-   -VALUE-
         two:    quick
         three:  brown
         four:   fox
         five:   jumped
         one:    The

 After Clear,
    Count    : 0
    Values:
         -KEY-   -VALUE-
 */

import System
import System.Collections
import Microsoft.VisualBasic

// Creates and initializes a new Hashtable.
var myHT : Hashtable = new Hashtable()
myHT.Add("one", "The")
myHT.Add("two", "quick")
myHT.Add("three", "brown")
myHT.Add("four", "fox")
myHT.Add("five", "jumped")

// Displays the count and values of the Hashtable.
Console.WriteLine("Initially,")
Console.WriteLine("   Count    : {0}", myHT.Count)
Console.WriteLine("   Values:")
PrintKeysAndValues(myHT)

// Clears the Hashtable.
myHT.Clear()

// Displays the count and values of the Hashtable.
Console.WriteLine("After Clear,")
Console.WriteLine("   Count    : {0}", myHT.Count)
Console.WriteLine("   Values:")
PrintKeysAndValues(myHT)
    
function PrintKeysAndValues(myList : Hashtable){
    var myEnumerator : IDictionaryEnumerator = myList.GetEnumerator()
    Console.WriteLine("\t-KEY-\t-VALUE-")
    while(myEnumerator.MoveNext())
        Console.WriteLine("\t{0}:\t{1}", myEnumerator.Key, myEnumerator.Value)
    Console.WriteLine()
}

// This code produces the following output.
// 
// Initially,
//    Count    : 5
//    Values:
//     -KEY-    -VALUE-
//     five:    jumped
//     three:   brown
//     four:    fox
//     two:     quick
//     one:     The
// 
// After Clear,
//    Count    : 0
//    Values:
//     -KEY-    -VALUE- 

Plattformen

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Versionsinformationen

.NET Framework

Unterstützt in: 2.0, 1.1, 1.0

.NET Compact Framework

Unterstützt in: 2.0, 1.0

Siehe auch

Referenz

Hashtable-Klasse
Hashtable-Member
System.Collections-Namespace
IDictionary.Clear