Hashtable.Clear Método

Definición

Espacio de nombres:

System.Collections

Ensamblado:

System.Runtime.dll

Source:

Hashtable.cs

Quita todos los elementos de Hashtable.

public:
 virtual void Clear();

public virtual void Clear ();

abstract member Clear : unit -> unit
override this.Clear : unit -> unit

Public Overridable Sub Clear ()

Implementaciones

Clear()

Excepciones

NotSupportedException

Hashtable es de solo lectura.

Ejemplos

En el ejemplo siguiente se muestra cómo borrar los valores de Hashtable.

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", "jumps" );
   
   // 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:   jumps
         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.
      var myHT = new Hashtable();
      myHT.Add("one", "The");
      myHT.Add("two", "quick");
      myHT.Add("three", "brown");
      myHT.Add("four", "fox");
      myHT.Add("five", "jumps");

      // Displays the count and values of the Hashtable.
      Console.WriteLine("Initially,");
      Console.WriteLine($"   Count    : {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    : {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{de.Key}:\t{de.Value}");
      Console.WriteLine();
   }
}


/*
This code produces the following output.

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

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

*/

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", "jumps")

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

    End Sub


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

End Class


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

Comentarios

Count se establece en cero y también se liberan las referencias a otros objetos de los elementos de la colección. La capacidad permanece sin cambios.

Este método es una O(n) operación, donde n es Count.

Consulte también

• Clear()