StringDictionary.ContainsValue(String) Método
Definição
Determina se o StringDictionary contém um valor específico.Determines if the StringDictionary contains a specific value.
public:
virtual bool ContainsValue(System::String ^ value);
public virtual bool ContainsValue (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
Parâmetros
- value
- String
O valor a ser localizado na StringDictionary.The value to locate in the StringDictionary. O valor pode ser null.The value can be null.
Retornos
true se o StringDictionary contiver um elemento com o valor especificado; caso contrário, false.true if the StringDictionary contains an element with the specified value; otherwise, false.
Exemplos
O exemplo de código a seguir pesquisa um elemento em um StringDictionary .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".
Comentários
Os valores dos elementos de StringDictionary são comparados com o valor especificado usando o Object.Equals método.The values of the elements of the StringDictionary are compared to the specified value using the Object.Equals method.
Esse método executa uma pesquisa linear; Portanto, o tempo médio de execução é proporcional ao Count .This method performs a linear search; therefore, the average execution time is proportional to Count. Ou seja, esse método é uma operação O ( n ), em que n é Count .That is, this method is an O(n) operation, where n is Count.
A partir do .NET Framework 2,0, esse método usa os objetos da coleção Equals e os CompareTo métodos em item para determinar se item existe.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. Em versões anteriores do .NET Framework, essa decisão era tomada usando-se os métodos Equals e CompareTo do parâmetro item nos objetos na coleção.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.