StringDictionary.ContainsValue(String) Methode

Definition

Ermittelt, ob das StringDictionary einen bestimmten Wert enthält.Determines if the StringDictionary contains a specific value.

public:
 virtual bool ContainsValue(System::String ^ value);
public virtual bool ContainsValue (string value);
abstract member ContainsValue : string -> bool
override this.ContainsValue : string -> bool
Public Overridable Function ContainsValue (value As String) As Boolean

Parameter

value
String

Der im StringDictionary zu suchende Wert.The value to locate in the StringDictionary. Der Wert kann null sein.The value can be null.

Gibt zurück

true, wenn das StringDictionary ein Element mit dem angegebenen Wert enthält, andernfalls false.true if the StringDictionary contains an element with the specified value; otherwise, false.

Beispiele

Im folgenden Codebeispiel wird nach einem Element in einem StringDictionarygesucht.The following code example searches for an element in a StringDictionary.

#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
void PrintKeysAndValues( StringDictionary^ myCol )
{
   Console::WriteLine( "   KEY        VALUE" );
   IEnumerator^ enum0 = myCol->GetEnumerator();
   while ( enum0->MoveNext() )
   {
      DictionaryEntry^ de = safe_cast<DictionaryEntry^>(enum0->Current);
      Console::WriteLine( "   {0,-10} {1}", de->Key, de->Value );
   }

   Console::WriteLine();
}

int main()
{
   
   // Creates and initializes a new StringDictionary.
   StringDictionary^ myCol = gcnew StringDictionary;
   myCol->Add( "red", "rojo" );
   myCol->Add( "green", "verde" );
   myCol->Add( "blue", "azul" );
   
   // Displays the values in the StringDictionary.
   Console::WriteLine( "Initial contents of the StringDictionary:" );
   PrintKeysAndValues( myCol );
   
   // Searches for a key.
   if ( myCol->ContainsKey( "red" ) )
      Console::WriteLine( "The collection contains the key \"red\"." );
   else
      Console::WriteLine( "The collection does not contain the key \"red\"." );

   Console::WriteLine();
   
   // Searches for a value.
   if ( myCol->ContainsValue( "amarillo" ) )
      Console::WriteLine( "The collection contains the value \"amarillo\"." );
   else
      Console::WriteLine( "The collection does not contain the value \"amarillo\"." );

   Console::WriteLine();
}

/*
This code produces the following output.

Initial contents of the StringDictionary:
   KEY        VALUE
   green      verde
   red        rojo
   blue       azul

The collection contains the key "red".

The collection does not contain the value "amarillo".

*/
using System;
using System.Collections;
using System.Collections.Specialized;

public class SamplesStringDictionary  {

   public static void Main()  {

      // Creates and initializes a new StringDictionary.
      StringDictionary myCol = new StringDictionary();
      myCol.Add( "red", "rojo" );
      myCol.Add( "green", "verde" );
      myCol.Add( "blue", "azul" );

      // Displays the values in the StringDictionary.
      Console.WriteLine( "Initial contents of the StringDictionary:" );
      PrintKeysAndValues( myCol );

      // Searches for a key.
      if ( myCol.ContainsKey( "red" ) )
         Console.WriteLine( "The collection contains the key \"red\"." );
      else
         Console.WriteLine( "The collection does not contain the key \"red\"." );
      Console.WriteLine();

      // Searches for a value.
      if ( myCol.ContainsValue( "amarillo" ) )
         Console.WriteLine( "The collection contains the value \"amarillo\"." );
      else
         Console.WriteLine( "The collection does not contain the value \"amarillo\"." );
      Console.WriteLine();

   }

   public static void PrintKeysAndValues( StringDictionary myCol )  {
      Console.WriteLine( "   KEY        VALUE" );
      foreach ( DictionaryEntry de in myCol )
         Console.WriteLine( "   {0,-10} {1}", de.Key, de.Value );
      Console.WriteLine();
   }

}

/*
This code produces the following output.

Initial contents of the StringDictionary:
   KEY        VALUE
   green      verde
   red        rojo
   blue       azul

The collection contains the key "red".

The collection does not contain the value "amarillo".

*/
Imports System.Collections
Imports System.Collections.Specialized

Public Class SamplesStringDictionary   

   Public Shared Sub Main()

      ' Creates and initializes a new StringDictionary.
      Dim myCol As New StringDictionary()
      myCol.Add("red", "rojo")
      myCol.Add("green", "verde")
      myCol.Add("blue", "azul")

      ' Displays the values in the StringDictionary.
      Console.WriteLine("Initial contents of the StringDictionary:")
      PrintKeysAndValues(myCol)

      ' Searches for a key.
      If myCol.ContainsKey("red") Then
         Console.WriteLine("The collection contains the key ""red"".")
      Else
         Console.WriteLine("The collection does not contain the key ""red"".")
      End If
      Console.WriteLine()

      ' Searches for a value.
      If myCol.ContainsValue("amarillo") Then
         Console.WriteLine("The collection contains the value ""amarillo"".")
      Else
         Console.WriteLine("The collection does not contain the value ""amarillo"".")
      End If
      Console.WriteLine()

   End Sub

   Public Shared Sub PrintKeysAndValues(myCol As StringDictionary)
      Dim de As DictionaryEntry

      Console.WriteLine("   KEY        VALUE")
      For Each de In  myCol
         Console.WriteLine("   {0,-10} {1}", de.Key, de.Value)
      Next de
      Console.WriteLine()

   End Sub

End Class


'This code produces the following output.
'
'Initial contents of the StringDictionary:
'   KEY        VALUE
'   green      verde
'   red        rojo
'   blue       azul
'
'The collection contains the key "red".
'
'The collection does not contain the value "amarillo".

Hinweise

Die Werte der Elemente des StringDictionary werden mithilfe der Object.Equals-Methode mit dem angegebenen Wert verglichen.The values of the elements of the StringDictionary are compared to the specified value using the Object.Equals method.

Diese Methode führt eine lineare Suche aus. Daher ist die durchschnittliche Ausführungszeit proportional zum Count.This method performs a linear search; therefore, the average execution time is proportional to Count. Das heißt, diese Methode ist ein O (n)-Vorgang, bei dem n Countist.That is, this method is an O(n) operation, where n is Count.

Beginnend mit dem .NET Framework 2,0 verwendet diese Methode die Equals-und CompareTo Methoden der Auflistung der-Objekte auf item, um zu bestimmen, ob item vorhanden ist.Starting with the .NET Framework 2.0, this method uses the collection's objects' Equals and CompareTo methods on item to determine whether item exists. In früheren Versionen der .NET Framework wurde diese Bestimmung mithilfe der Methoden Equals und CompareTo des item-Parameters für die Objekte in der Auflistung fest gemacht.In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the item parameter on the objects in the collection.

Gilt für:

Siehe auch