NameObjectCollectionBase.BaseGet Método

Definición

Espacio de nombres:

System.Collections.Specialized

Ensamblado:

System.Collections.Specialized.dll

Obtiene el valor de la entrada especificada desde la instancia NameObjectCollectionBase.

Sobrecargas

BaseGet(Int32)	Obtiene el valor de la entrada que se encuentra en el índice especificado de la instancia NameObjectCollectionBase.
BaseGet(String)	Obtiene el valor de la primera entrada con la clave especificada desde la instancia NameObjectCollectionBase.

Ejemplos

En el ejemplo de código siguiente se usa BaseGetKey y BaseGet para obtener claves y valores específicos.

#using <System.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;

public ref class MyCollection : public NameObjectCollectionBase  {

private:
   DictionaryEntry^ _de;

   // Gets a key-and-value pair (DictionaryEntry) using an index.
public:
   property DictionaryEntry^ default[ int ]  {
      DictionaryEntry^ get( int index )  {
         _de->Key = this->BaseGetKey( index );
         _de->Value = this->BaseGet( index );
         return( _de );
      }
   }

   // Gets or sets the value associated with the specified key.
   property Object^ default[ String^ ]  {
      Object^ get(String^ key)  {
         return( this->BaseGet( key ) );
      }
      void set( String^ key, Object^ value )  {
         this->BaseSet( key, value );
      }
   }

   // Adds elements from an IDictionary into the new collection.
   MyCollection( IDictionary^ d )  {

      _de = gcnew DictionaryEntry();

      for each ( DictionaryEntry^ de in d )  {
         this->BaseAdd( (String^) de->Key, de->Value );
      }
   }
};

public ref class SamplesNameObjectCollectionBase  {

public:
   static void Main()  {

      // Creates and initializes a new MyCollection instance.
      IDictionary^ d = gcnew ListDictionary();
      d->Add( "red", "apple" );
      d->Add( "yellow", "banana" );
      d->Add( "green", "pear" );
      MyCollection^ myCol = gcnew MyCollection( d );
      Console::WriteLine( "Initial state of the collection (Count = {0}):", myCol->Count );
      PrintKeysAndValues( myCol );

      // Gets specific keys and values.
      Console::WriteLine( "The key at index 0 is {0}.", myCol[0]->Key );
      Console::WriteLine( "The value at index 0 is {0}.", myCol[0]->Value );
      Console::WriteLine( "The value associated with the key \"green\" is {0}.", myCol["green"] );

   }

   static void PrintKeysAndValues( MyCollection^ myCol )  {
      for ( int i = 0; i < myCol->Count; i++ )  {
         Console::WriteLine( "[{0}] : {1}, {2}", i, myCol[i]->Key, myCol[i]->Value );
      }
   }
};

int main()
{
    SamplesNameObjectCollectionBase::Main();
}

/*
This code produces the following output.

Initial state of the collection (Count = 3):
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
The key at index 0 is red.
The value at index 0 is apple.
The value associated with the key "green" is pear.

*/

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

public class MyCollection : NameObjectCollectionBase  {

   private DictionaryEntry _de = new DictionaryEntry();

   // Gets a key-and-value pair (DictionaryEntry) using an index.
   public DictionaryEntry this[ int index ]  {
      get  {
         _de.Key = this.BaseGetKey( index );
         _de.Value = this.BaseGet( index );
         return( _de );
      }
   }

   // Gets or sets the value associated with the specified key.
   public Object this[ String key ]  {
      get  {
         return( this.BaseGet( key ) );
      }
      set  {
         this.BaseSet( key, value );
      }
   }

   // Adds elements from an IDictionary into the new collection.
   public MyCollection( IDictionary d )  {
      foreach ( DictionaryEntry de in d )  {
         this.BaseAdd( (String) de.Key, de.Value );
      }
   }
}

public class SamplesNameObjectCollectionBase  {

   public static void Main()  {

      // Creates and initializes a new MyCollection instance.
      IDictionary d = new ListDictionary();
      d.Add( "red", "apple" );
      d.Add( "yellow", "banana" );
      d.Add( "green", "pear" );
      MyCollection myCol = new MyCollection( d );
      Console.WriteLine( "Initial state of the collection (Count = {0}):", myCol.Count );
      PrintKeysAndValues( myCol );

      // Gets specific keys and values.
      Console.WriteLine( "The key at index 0 is {0}.", myCol[0].Key );
      Console.WriteLine( "The value at index 0 is {0}.", myCol[0].Value );
      Console.WriteLine( "The value associated with the key \"green\" is {0}.", myCol["green"] );
   }

   public static void PrintKeysAndValues( MyCollection myCol )  {
      for ( int i = 0; i < myCol.Count; i++ )  {
         Console.WriteLine( "[{0}] : {1}, {2}", i, myCol[i].Key, myCol[i].Value );
      }
   }
}


/*
This code produces the following output.

Initial state of the collection (Count = 3):
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
The key at index 0 is red.
The value at index 0 is apple.
The value associated with the key "green" is pear.

*/

Imports System.Collections
Imports System.Collections.Specialized

Public Class MyCollection
   Inherits NameObjectCollectionBase

   Private _de As New DictionaryEntry()

   ' Gets a key-and-value pair (DictionaryEntry) using an index.
   Default Public ReadOnly Property Item(index As Integer) As DictionaryEntry
      Get
         _de.Key = Me.BaseGetKey(index)
         _de.Value = Me.BaseGet(index)
         Return _de
      End Get
   End Property

   ' Gets or sets the value associated with the specified key.
   Default Public Property Item(key As [String]) As [Object]
      Get
         Return Me.BaseGet(key)
      End Get
      Set
         Me.BaseSet(key, value)
      End Set
   End Property

   ' Adds elements from an IDictionary into the new collection.
   Public Sub New(d As IDictionary)
      Dim de As DictionaryEntry
      For Each de In  d
         Me.BaseAdd(CType(de.Key, [String]), de.Value)
      Next de
   End Sub

End Class


Public Class SamplesNameObjectCollectionBase   

   Public Shared Sub Main()

      ' Creates and initializes a new MyCollection instance.
      Dim d = New ListDictionary()
      d.Add("red", "apple")
      d.Add("yellow", "banana")
      d.Add("green", "pear")
      Dim myCol As New MyCollection(d)
      Console.WriteLine("Initial state of the collection (Count = {0}):", myCol.Count)
      PrintKeysAndValues(myCol)

      ' Gets specific keys and values.
      Console.WriteLine("The key at index 0 is {0}.", myCol(0).Key)
      Console.WriteLine("The value at index 0 is {0}.", myCol(0).Value)
      Console.WriteLine("The value associated with the key ""green"" is {0}.", myCol("green"))

   End Sub

   Public Shared Sub PrintKeysAndValues(myCol As MyCollection)
      Dim i As Integer
      For i = 0 To myCol.Count - 1
         Console.WriteLine("[{0}] : {1}, {2}", i, myCol(i).Key, myCol(i).Value)
      Next i
   End Sub

End Class


'This code produces the following output.
'
'Initial state of the collection (Count = 3):
'[0] : red, apple
'[1] : yellow, banana
'[2] : green, pear
'The key at index 0 is red.
'The value at index 0 is apple.
'The value associated with the key "green" is pear.

BaseGet(Int32)

Source:

NameObjectCollectionBase.cs

Obtiene el valor de la entrada que se encuentra en el índice especificado de la instancia NameObjectCollectionBase.

protected:
 System::Object ^ BaseGet(int index);

protected object? BaseGet (int index);

member this.BaseGet : int -> obj

Protected Function BaseGet (index As Integer) As Object

Parámetros

index

Int32

Índice de base cero del valor que se va a obtener.

Devoluciones

Object

Object que representa el valor de la entrada que se encuentra en el índice especificado.

Excepciones

ArgumentOutOfRangeException

index está fuera del intervalo válido de índices de la colección.

Comentarios

Este método es una operación O(1).

BaseGet(String)

Source:

NameObjectCollectionBase.cs

Obtiene el valor de la primera entrada con la clave especificada desde la instancia NameObjectCollectionBase.

protected:
 System::Object ^ BaseGet(System::String ^ name);

protected object? BaseGet (string? name);

member this.BaseGet : string -> obj

Protected Function BaseGet (name As String) As Object

Parámetros

name

String

Clave String de la entrada que se va a obtener. La clave puede ser null.

Devoluciones

Object

Object que representa el valor de la primera entrada con la clave especificada, si se encuentra; en caso contrario, es null.

Comentarios

Si la colección contiene varias entradas con la clave especificada, este método devuelve solo la primera entrada. Para obtener los valores de las entradas posteriores con la misma clave, use el enumerador para recorrer en iteración la colección y comparar las claves.

Precaución

Este método devuelve null en los casos siguientes: 1) si no se encuentra la clave especificada; y 2) si se encuentra la clave especificada y su valor asociado es null. Este método no distingue entre los dos casos.

Este método es una operación O(1).

Consulte también

• GetEnumerator()