StringCollection.Contains-Methode

Bestimmt, ob sich die angegebene Zeichenfolge in der StringCollection befindet.

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

Syntax

'Declaration
Public Function Contains ( _
    value As String _
) As Boolean
'Usage
Dim instance As StringCollection
Dim value As String
Dim returnValue As Boolean

returnValue = instance.Contains(value)

public bool Contains (
    string value
)

public:
bool Contains (
    String^ value
)

public boolean Contains (
    String value
)

public function Contains (
    value : String
) : boolean

Parameter

• value
  Die in der StringCollection zu suchende Zeichenfolge. Der Wert kann NULL (Nothing in Visual Basic) sein.

Rückgabewert

true, wenn sich value in StringCollection befindet; andernfalls false.

Hinweise

Mit der Contains-Methode kann vor dem Ausführen anderer Operationen das Vorhandensein einer Zeichenfolge bestätigt werden.

Diese Methode ruft Object.Equals für die Gleichheitsprüfung auf. Bei Zeichenfolgenvergleichen wird die Groß- und Kleinschreibung berücksichtigt.

Diese Methode führt eine lineare Suche durch. Daher ist diese Methode eine O(n)-Operation, wobei n gleich Count ist.

Beispiel

Im folgenden Codebeispiel wird ein Element in der StringCollection gesucht.

Imports System
Imports System.Collections
Imports System.Collections.Specialized

Public Class SamplesStringCollection   

   Public Shared Sub Main()

      ' Creates and initializes a new StringCollection.
      Dim myCol As New StringCollection()
      Dim myArr() As [String] = {"RED", "orange", "yellow", "RED", "green", "blue", "RED", "indigo", "violet", "RED"}
      myCol.AddRange(myArr)

      Console.WriteLine("Initial contents of the StringCollection:")
      PrintValues(myCol)

      ' Checks whether the collection contains "orange" and, if so, displays its index.
      If myCol.Contains("orange") Then
         Console.WriteLine("The collection contains ""orange"" at index {0}.", myCol.IndexOf("orange"))
      Else
         Console.WriteLine("The collection does not contain ""orange"".")
      End If 

   End Sub 'Main

   Public Shared Sub PrintValues(myCol As IEnumerable)
      Dim obj As [Object]
      For Each obj In  myCol
         Console.WriteLine("   {0}", obj)
      Next obj
      Console.WriteLine()
   End Sub 'PrintValues

End Class 'SamplesStringCollection 


'This code produces the following output.
'
'Initial contents of the StringCollection:
'   RED
'   orange
'   yellow
'   RED
'   green
'   blue
'   RED
'   indigo
'   violet
'   RED
'
'The collection contains "orange" at index 1.
'

using System;
using System.Collections;
using System.Collections.Specialized;

public class SamplesStringCollection  {

   public static void Main()  {

      // Creates and initializes a new StringCollection.
      StringCollection myCol = new StringCollection();
      String[] myArr = new String[] { "RED", "orange", "yellow", "RED", "green", "blue", "RED", "indigo", "violet", "RED" };
      myCol.AddRange( myArr );

      Console.WriteLine( "Initial contents of the StringCollection:" );
      PrintValues( myCol );

      // Checks whether the collection contains "orange" and, if so, displays its index.
      if ( myCol.Contains( "orange" ) )
         Console.WriteLine( "The collection contains \"orange\" at index {0}.", myCol.IndexOf( "orange" ) );
      else
         Console.WriteLine( "The collection does not contain \"orange\"." );

   }

   public static void PrintValues( IEnumerable myCol )  {
      foreach ( Object obj in myCol )
         Console.WriteLine( "   {0}", obj );
      Console.WriteLine();
   }

}

/*
This code produces the following output.

Initial contents of the StringCollection:
   RED
   orange
   yellow
   RED
   green
   blue
   RED
   indigo
   violet
   RED

The collection contains "orange" at index 1.

*/

#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
void PrintValues( IEnumerable^ myCol );
int main()
{
   
   // Creates and initializes a new StringCollection.
   StringCollection^ myCol = gcnew StringCollection;
   array<String^>^myArr = {"RED","orange","yellow","RED","green","blue","RED","indigo","violet","RED"};
   myCol->AddRange( myArr );
   Console::WriteLine( "Initial contents of the StringCollection:" );
   PrintValues( myCol );
   
   // Checks whether the collection contains "orange" and, if so, displays its index.
   if ( myCol->Contains( "orange" ) )
      Console::WriteLine( "The collection contains \"orange\" at index {0}.", myCol->IndexOf( "orange" ) );
   else
      Console::WriteLine( "The collection does not contain \"orange\"." );
}

void PrintValues( IEnumerable^ myCol )
{
   IEnumerator^ myEnum = myCol->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ obj = safe_cast<Object^>(myEnum->Current);
      Console::WriteLine( "   {0}", obj );
   }

   Console::WriteLine();
}

/*
This code produces the following output.

Initial contents of the StringCollection:
   RED
   orange
   yellow
   RED
   green
   blue
   RED
   indigo
   violet
   RED

The collection contains "orange" at index 1.

*/

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

public class SamplesStringCollection
{
    public static void main(String[] args)
    {
        // Creates and initializes a new StringCollection.
        StringCollection myCol =  new StringCollection();
        String myArr[] = new String[]{"RED", "orange", "yellow", "RED",
            "green", "blue", "RED", "indigo", "violet", "RED"};
        myCol.AddRange(myArr);
            
        Console.WriteLine("Initial contents of the StringCollection:");
        PrintValues(myCol);
            
        // Checks whether the collection contains "orange" and, if so,
        // displays its index.
        if ( myCol.Contains("orange")) {
            Console.WriteLine("The collection contains \"orange\" at index"
                + " {0}.",System.Convert.ToString(myCol.IndexOf("orange")));
        }
        else {        
            Console.WriteLine("The collection does not contain \"orange\".");
        } 
    } //main        
        
    public static void PrintValues(IEnumerable myCol)
    {
        Object obj = null;
        IEnumerator objEnum = myCol.GetEnumerator();

        while (objEnum.MoveNext()) {        
            obj = objEnum.get_Current();
            Console.WriteLine("   {0}", obj);
        }

        Console.WriteLine();
    } //PrintValues
} //SamplesStringCollection 

/*
This code produces the following output.

Initial contents of the StringCollection:
   RED
   orange
   yellow
   RED
   green
   blue
   RED
   indigo
   violet
   RED

The collection contains "orange" at index 1.

*/

Plattformen

Windows 98, Windows 2000 SP4, Windows Millennium Edition, 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

Siehe auch

Referenz

StringCollection-Klasse
StringCollection-Member
System.Collections.Specialized-Namespace
IndexOf

Weitere Ressourcen

Durchführen kulturunabhängiger Zeichenfolgenoperationen