SortedList.ContainsKey(Object) Metodo

Riferimento

Definizione

Spazio dei nomi:: System.Collections

Assembly:: mscorlib.dll, System.Collections.NonGeneric.dll

Assembly:: System.Collections.NonGeneric.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: SortedList.cs

Source:: SortedList.cs

Source:: SortedList.cs

Importante

Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.

Determina se un oggetto SortedList contiene una chiave specifica.

public:
 virtual bool ContainsKey(System::Object ^ key);

public virtual bool ContainsKey (object key);

abstract member ContainsKey : obj -> bool
override this.ContainsKey : obj -> bool

Public Overridable Function ContainsKey (key As Object) As Boolean

Parametri

key: Object

Chiave da individuare nell'oggetto SortedList.

Restituisce

Boolean

true se l'oggetto SortedList contiene un elemento con il parametro key specificato; in caso contrario, false.

Eccezioni

ArgumentNullException

key è null.

InvalidOperationException

L'operatore di confronto genera un'eccezione.

Esempio

Nell'esempio di codice seguente viene illustrato come determinare se un SortedList oggetto contiene un elemento specifico.

#using <system.dll>

using namespace System;
using namespace System::Collections;
void PrintIndexAndKeysAndValues( SortedList^ myList )
{
   Console::WriteLine(  "\t-INDEX-\t-KEY-\t-VALUE-" );
   for ( int i = 0; i < myList->Count; i++ )
   {
      Console::WriteLine(  "\t[{0}]:\t{1}\t{2}", i, myList->GetKey( i ), myList->GetByIndex( i ) );

   }
   Console::WriteLine();
}

int main()
{
   
   // Creates and initializes a new SortedList.
   SortedList^ mySL = gcnew SortedList;
   mySL->Add( 2, "two" );
   mySL->Add( 4, "four" );
   mySL->Add( 1, "one" );
   mySL->Add( 3, "three" );
   mySL->Add( (int^)0, "zero" );
   
   // Displays the values of the SortedList.
   Console::WriteLine(  "The SortedList contains the following values:" );
   PrintIndexAndKeysAndValues( mySL );
   
   // Searches for a specific key.
   int myKey = 2;
   Console::WriteLine(  "The key \"{0}\" is {1}.", myKey, mySL->ContainsKey( myKey ) ? (String^)"in the SortedList" : "NOT in the SortedList" );
   myKey = 6;
   Console::WriteLine(  "The key \"{0}\" is {1}.", myKey, mySL->ContainsKey( myKey ) ? (String^)"in the SortedList" : "NOT in the SortedList" );
   
   // Searches for a specific value.
   String^ myValue = "three";
   Console::WriteLine(  "The value \"{0}\" is {1}.", myValue, mySL->ContainsValue( myValue ) ? (String^)"in the SortedList" : "NOT in the SortedList" );
   myValue =  "nine";
   Console::WriteLine(  "The value \"{0}\" is {1}.", myValue, mySL->ContainsValue( myValue ) ? (String^)"in the SortedList" : "NOT in the SortedList" );
}

/* 
This code produces the following output.

The SortedList contains the following values:
        -INDEX- -KEY-   -VALUE-
        [0]:    0       zero
        [1]:    1       one
        [2]:    2       two
        [3]:    3       three
        [4]:    4       four

The key "2" is in the SortedList.
The key "6" is NOT in the SortedList.
The value "three" is in the SortedList.
The value "nine" is NOT in the SortedList.
*/

using System;
using System.Collections;

public class SamplesSortedList  {

   public static void Main()  {

      // Creates and initializes a new SortedList.
      SortedList mySL = new SortedList();
      mySL.Add( 2, "two" );
      mySL.Add( 4, "four" );
      mySL.Add( 1, "one" );
      mySL.Add( 3, "three" );
      mySL.Add( 0, "zero" );

      // Displays the values of the SortedList.
      Console.WriteLine( "The SortedList contains the following values:" );
      PrintIndexAndKeysAndValues( mySL );

      // Searches for a specific key.
      int myKey = 2;
      Console.WriteLine( "The key \"{0}\" is {1}.", myKey, mySL.ContainsKey( myKey ) ? "in the SortedList" : "NOT in the SortedList" );
      myKey = 6;
      Console.WriteLine( "The key \"{0}\" is {1}.", myKey, mySL.ContainsKey( myKey ) ? "in the SortedList" : "NOT in the SortedList" );

      // Searches for a specific value.
      string myValue = "three";
      Console.WriteLine( "The value \"{0}\" is {1}.", myValue, mySL.ContainsValue( myValue ) ? "in the SortedList" : "NOT in the SortedList" );
      myValue = "nine";
      Console.WriteLine( "The value \"{0}\" is {1}.", myValue, mySL.ContainsValue( myValue ) ? "in the SortedList" : "NOT in the SortedList" );
   }

   public static void PrintIndexAndKeysAndValues( SortedList myList )  {
      Console.WriteLine( "\t-INDEX-\t-KEY-\t-VALUE-" );
      for ( int i = 0; i < myList.Count; i++ )  {
         Console.WriteLine( "\t[{0}]:\t{1}\t{2}", i, myList.GetKey(i), myList.GetByIndex(i) );
      }
      Console.WriteLine();
   }
}
/*
This code produces the following output.

The SortedList contains the following values:
    -INDEX-    -KEY-    -VALUE-
    [0]:    0    zero
    [1]:    1    one
    [2]:    2    two
    [3]:    3    three
    [4]:    4    four

The key "2" is in the SortedList.
The key "6" is NOT in the SortedList.
The value "three" is in the SortedList.
The value "nine" is NOT in the SortedList.
*/

Imports System.Collections

Public Class SamplesSortedList    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new SortedList.
        Dim mySL As New SortedList()
        mySL.Add(2, "two")
        mySL.Add(4, "four")
        mySL.Add(1, "one")
        mySL.Add(3, "three")
        mySL.Add(0, "zero")
        
        ' Displays the values of the SortedList.
        Console.WriteLine("The SortedList contains the following values:")
        PrintIndexAndKeysAndValues(mySL)
        
        ' Searches for a specific key.
        Dim myKey As Integer = 2
        Dim msg As String
        If mySL.ContainsKey(myKey) Then
            msg = "in the SortedList"
        Else
            msg = "NOT in the SortedList"
        End If
        Console.WriteLine("The key ""{0}"" is {1}.", myKey, msg)
        myKey = 6
        If mySL.ContainsKey(myKey) Then
            msg = "in the SortedList"
        Else
            msg = "NOT in the SortedList"
        End If
        Console.WriteLine("The key ""{0}"" is {1}.", myKey, msg)        
        ' Searches for a specific value.
        Dim myValue As String = "three"
        If mySL.ContainsValue(myValue) Then
            msg = "in the SortedList"
        Else
            msg = "NOT in the SortedList"
        End If
        Console.WriteLine("The value ""{0}"" is {1}.", myValue, msg)
        myValue = "nine"
        If mySL.ContainsValue(myValue) Then
            msg = "in the SortedList"
        Else
            msg = "NOT in the SortedList"
        End If
        Console.WriteLine("The value ""{0}"" is {1}.", myValue, msg)
    End Sub   
    
    
    Public Shared Sub PrintIndexAndKeysAndValues(myList As SortedList)
        Console.WriteLine(ControlChars.Tab & "-INDEX-" & ControlChars.Tab & _
           "-KEY-" & ControlChars.Tab & "-VALUE-")
        Dim i As Integer
        For i = 0 To myList.Count - 1
            Console.WriteLine(ControlChars.Tab & "[{0}]:" & ControlChars.Tab & _
               "{1}" & ControlChars.Tab & "{2}", i, myList.GetKey(i), _
               myList.GetByIndex(i))
        Next i
        Console.WriteLine()
    End Sub
End Class

' This code produces the following output.
' 
' The SortedList contains the following values:
'     -INDEX-    -KEY-    -VALUE-
'     [0]:    0    zero
'     [1]:    1    one
'     [2]:    2    two
'     [3]:    3    three
'     [4]:    4    four
' 
' The key "2" is in the SortedList.
' The key "6" is NOT in the SortedList.
' The value "three" is in the SortedList.
' The value "nine" is NOT in the SortedList.

Commenti

Gli elementi di un SortedList oggetto vengono ordinati in base alle chiavi in base a un'implementazione specifica IComparer specificata quando SortedList viene creato o in base all'implementazione IComparable fornita dalle chiavi stesse.

Questo metodo si comporta esattamente come il Contains metodo .

Questo metodo usa un algoritmo di ricerca binaria; pertanto, questo metodo è un'operazione O(log n) , dove n è Count.

A partire da .NET Framework 2.0, questo metodo usa i metodi e CompareTo gli oggetti Equals della raccolta per item determinare se l'elemento esiste. Nelle versioni precedenti di .NET Framework questa determinazione è stata effettuata usando i Equals metodi e CompareTo del item parametro sugli oggetti nella raccolta.

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