ReadOnlyCollectionBase ReadOnlyCollectionBase ReadOnlyCollectionBase ReadOnlyCollectionBase Class

Definición

Proporciona la clase base abstract de una colección de sólo lectura no genérica fuertemente tipada.Provides the abstract base class for a strongly typed non-generic read-only collection.

public ref class ReadOnlyCollectionBase abstract : System::Collections::ICollection
[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public abstract class ReadOnlyCollectionBase : System.Collections.ICollection
type ReadOnlyCollectionBase = class
    interface ICollection
    interface IEnumerable
Public MustInherit Class ReadOnlyCollectionBase
Implements ICollection
Herencia
ReadOnlyCollectionBaseReadOnlyCollectionBaseReadOnlyCollectionBaseReadOnlyCollectionBase
Derivado
Atributos
Implementaciones

Ejemplos

En el ejemplo de código siguiente se ReadOnlyCollectionBase implementa la clase.The following code example implements the ReadOnlyCollectionBase class.

using namespace System;
using namespace System::Collections;
public ref class ROCollection: public ReadOnlyCollectionBase
{
public:
   ROCollection( IList^ sourceList )
   {
      InnerList->AddRange( sourceList );
   }

   property Object^ Item [int]
   {
      Object^ get( int index )
      {
         return (InnerList[ index ]);
      }

   }
   int IndexOf( Object^ value )
   {
      return (InnerList->IndexOf( value ));
   }

   bool Contains( Object^ value )
   {
      return (InnerList->Contains( value ));
   }

};

void PrintIndexAndValues( ROCollection^ myCol );
void PrintValues2( ROCollection^ myCol );
int main()
{
   // Create an ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "red" );
   myAL->Add( "blue" );
   myAL->Add( "yellow" );
   myAL->Add( "green" );
   myAL->Add( "orange" );
   myAL->Add( "purple" );

   // Create a new ROCollection that contains the elements in myAL.
   ROCollection^ myCol = gcnew ROCollection( myAL );

   // Display the contents of the collection using the enumerator.
   Console::WriteLine( "Contents of the collection (using enumerator):" );
   PrintValues2( myCol );

   // Display the contents of the collection using the Count property and the Item property.
   Console::WriteLine( "Contents of the collection (using Count and Item):" );
   PrintIndexAndValues( myCol );

   // Search the collection with Contains and IndexOf.
   Console::WriteLine( "Contains yellow: {0}", myCol->Contains( "yellow" ) );
   Console::WriteLine( "orange is at index {0}.", myCol->IndexOf( "orange" ) );
   Console::WriteLine();
}


// Uses the Count property and the Item property.
void PrintIndexAndValues( ROCollection^ myCol )
{
   for ( int i = 0; i < myCol->Count; i++ )
      Console::WriteLine( "   [{0}]:   {1}", i, myCol->Item[ i ] );
   Console::WriteLine();
}


// Uses the enumerator. 
void PrintValues2( ROCollection^ myCol )
{
   System::Collections::IEnumerator^ myEnumerator = myCol->GetEnumerator();
   while ( myEnumerator->MoveNext() )
      Console::WriteLine( "   {0}", myEnumerator->Current );

   Console::WriteLine();
}

/* 
This code produces the following output.

Contents of the collection (using enumerator):
   red
   blue
   yellow
   green
   orange
   purple

Contents of the collection (using Count and Item):
   [0]:   red
   [1]:   blue
   [2]:   yellow
   [3]:   green
   [4]:   orange
   [5]:   purple

Contains yellow: True
orange is at index 4.

*/
using System;
using System.Collections;

public class ROCollection : ReadOnlyCollectionBase  {

   public ROCollection( IList sourceList )  {
      InnerList.AddRange( sourceList );
   }

   public Object this[ int index ]  {
      get  {
         return( InnerList[index] );
      }
   }

   public int IndexOf( Object value )  {
      return( InnerList.IndexOf( value ) );
   }

   public bool Contains( Object value )  {
      return( InnerList.Contains( value ) );
   }

}


public class SamplesCollectionBase  {

   public static void Main()  {

      // Create an ArrayList.
      ArrayList myAL = new ArrayList();
      myAL.Add( "red" );
      myAL.Add( "blue" );
      myAL.Add( "yellow" );
      myAL.Add( "green" );
      myAL.Add( "orange" );
      myAL.Add( "purple" );
 
      // Create a new ROCollection that contains the elements in myAL.
      ROCollection myCol = new ROCollection( myAL );

      // Display the contents of the collection using foreach. This is the preferred method.
      Console.WriteLine( "Contents of the collection (using foreach):" );
      PrintValues1( myCol );

      // Display the contents of the collection using the enumerator.
      Console.WriteLine( "Contents of the collection (using enumerator):" );
      PrintValues2( myCol );

      // Display the contents of the collection using the Count property and the Item property.
      Console.WriteLine( "Contents of the collection (using Count and Item):" );
      PrintIndexAndValues( myCol );

      // Search the collection with Contains and IndexOf.
      Console.WriteLine( "Contains yellow: {0}", myCol.Contains( "yellow" ) );
      Console.WriteLine( "orange is at index {0}.", myCol.IndexOf( "orange" ) );
      Console.WriteLine();

   }
 
   // Uses the Count property and the Item property.
   public static void PrintIndexAndValues( ROCollection myCol )  {
      for ( int i = 0; i < myCol.Count; i++ )
         Console.WriteLine( "   [{0}]:   {1}", i, myCol[i] );
      Console.WriteLine();
   }

   // Uses the foreach statement which hides the complexity of the enumerator.
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintValues1( ROCollection myCol )  {
      foreach ( Object obj in myCol )
         Console.WriteLine( "   {0}", obj );
      Console.WriteLine();
   }

   // Uses the enumerator. 
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintValues2( ROCollection myCol )  {
      System.Collections.IEnumerator myEnumerator = myCol.GetEnumerator();
      while ( myEnumerator.MoveNext() )
         Console.WriteLine( "   {0}", myEnumerator.Current );
      Console.WriteLine();
   }

}


/* 
This code produces the following output.

Contents of the collection (using foreach):
   red
   blue
   yellow
   green
   orange
   purple

Contents of the collection (using enumerator):
   red
   blue
   yellow
   green
   orange
   purple

Contents of the collection (using Count and Item):
   [0]:   red
   [1]:   blue
   [2]:   yellow
   [3]:   green
   [4]:   orange
   [5]:   purple

Contains yellow: True
orange is at index 4.

*/

Imports System
Imports System.Collections

Public Class ROCollection
    Inherits ReadOnlyCollectionBase


    Public Sub New(sourceList As IList)
        InnerList.AddRange(sourceList)
    End Sub 'New


    Default Public ReadOnly Property Item(index As Integer) As [Object]
        Get
            Return InnerList(index)
        End Get
    End Property


    Public Function IndexOf(value As [Object]) As Integer
        Return InnerList.IndexOf(value)
    End Function 'IndexOf


    Public Function Contains(value As [Object]) As Boolean
        Return InnerList.Contains(value)
    End Function 'Contains

End Class 'ROCollection 


Public Class SamplesCollectionBase

    Public Shared Sub Main()

        ' Create an ArrayList.
        Dim myAL As New ArrayList()
        myAL.Add("red")
        myAL.Add("blue")
        myAL.Add("yellow")
        myAL.Add("green")
        myAL.Add("orange")
        myAL.Add("purple")

        ' Create a new ROCollection that contains the elements in myAL.
        Dim myCol As New ROCollection(myAL)

        ' Display the contents of the collection using For Each. This is the preferred method.
        Console.WriteLine("Contents of the collection (using For Each):")
        PrintValues1(myCol)

        ' Display the contents of the collection using the enumerator.
        Console.WriteLine("Contents of the collection (using enumerator):")
        PrintValues2(myCol)

        ' Display the contents of the collection using the Count property and the Item property.
        Console.WriteLine("Contents of the collection (using Count and Item):")
        PrintIndexAndValues(myCol)

        ' Search the collection with Contains and IndexOf.
        Console.WriteLine("Contains yellow: {0}", myCol.Contains("yellow"))
        Console.WriteLine("orange is at index {0}.", myCol.IndexOf("orange"))
        Console.WriteLine()

    End Sub 'Main


    ' Uses the Count property and the Item property.
    Public Shared Sub PrintIndexAndValues(myCol As ROCollection)
        Dim i As Integer
        For i = 0 To myCol.Count - 1
            Console.WriteLine("   [{0}]:   {1}", i, myCol(i))
        Next i
        Console.WriteLine()
    End Sub 'PrintIndexAndValues


    ' Uses the For Each statement which hides the complexity of the enumerator.
    ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
    Public Shared Sub PrintValues1(myCol As ROCollection)
        Dim obj As [Object]
        For Each obj In  myCol
            Console.WriteLine("   {0}", obj)
        Next obj
        Console.WriteLine()
    End Sub 'PrintValues1


    ' Uses the enumerator. 
    ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
    Public Shared Sub PrintValues2(myCol As ROCollection)
        Dim myEnumerator As System.Collections.IEnumerator = myCol.GetEnumerator()
        While myEnumerator.MoveNext()
            Console.WriteLine("   {0}", myEnumerator.Current)
        End While
        Console.WriteLine()
    End Sub 'PrintValues2

End Class 'SamplesCollectionBase 


'This code produces the following output.
'
'Contents of the collection (using For Each):
'   red
'   blue
'   yellow
'   green
'   orange
'   purple
'
'Contents of the collection (using enumerator):
'   red
'   blue
'   yellow
'   green
'   orange
'   purple
'
'Contents of the collection (using Count and Item):
'   [0]:   red
'   [1]:   blue
'   [2]:   yellow
'   [3]:   green
'   [4]:   orange
'   [5]:   purple
'
'Contains yellow: True
'orange is at index 4.

Comentarios

Una ReadOnlyCollectionBase instancia siempre es de solo lectura.A ReadOnlyCollectionBase instance is always read-only. Vea CollectionBase para obtener una versión modificable de esta clase.See CollectionBase for a modifiable version of this class.

Importante

No se recomienda usar la clase para ReadOnlyCollectionBase el nuevo desarrollo.We don't recommend that you use the ReadOnlyCollectionBase class for new development. En su lugar, se recomienda usar la clase genérica ReadOnlyCollection<T> .Instead, we recommend that you use the generic ReadOnlyCollection<T> class. Para obtener más información, consulte no se deben usar colecciones no genéricas en github.For more information, see Non-generic collections shouldn't be used on GitHub.

Notas a los desarrolladores de herederos

Esta clase base se proporciona para facilitar a los implementadores la creación de una colección personalizada fuertemente tipada de solo lectura.This base class is provided to make it easier for implementers to create a strongly typed read-only custom collection. Se recomienda a los implementadores que amplíen esta clase base en lugar de crear las suyas propias.Implementers are encouraged to extend this base class instead of creating their own. Los miembros de esta clase base están protegidos y están pensados para usarse solo a través de una clase derivada.Members of this base class are protected and are intended to be used through a derived class only.

Esta clase hace que la colección subyacente esté disponible InnerList a través de la propiedad, que está destinada a ser utilizada únicamente ReadOnlyCollectionBasepor las clases que se derivan directamente de.This class makes the underlying collection available through the InnerList property, which is intended for use only by classes that are derived directly from ReadOnlyCollectionBase. La clase derivada debe asegurarse de que sus propios usuarios no pueden modificar la colección subyacente.The derived class must ensure that its own users cannot modify the underlying collection.

Constructores

ReadOnlyCollectionBase() ReadOnlyCollectionBase() ReadOnlyCollectionBase() ReadOnlyCollectionBase()

Inicializa una nueva instancia de la clase ReadOnlyCollectionBase.Initializes a new instance of the ReadOnlyCollectionBase class.

Propiedades

Count Count Count Count

Obtiene el número de elementos incluidos en la instancia de ReadOnlyCollectionBase.Gets the number of elements contained in the ReadOnlyCollectionBase instance.

InnerList InnerList InnerList InnerList

Obtiene la lista de elementos incluidos en la instancia de ReadOnlyCollectionBase.Gets the list of elements contained in the ReadOnlyCollectionBase instance.

Métodos

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determina si el objeto especificado es igual al objeto actual.Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetEnumerator() GetEnumerator() GetEnumerator() GetEnumerator()

Devuelve un enumerador que recorre en iteración la instancia de ReadOnlyCollectionBase.Returns an enumerator that iterates through the ReadOnlyCollectionBase instance.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Sirve como la función hash predeterminada.Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Obtiene el Type de la instancia actual.Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Crea una copia superficial del objeto Object actual.Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Devuelve una cadena que representa el objeto actual.Returns a string that represents the current object.

(Inherited from Object)

Implementaciones de interfaz explícitas

ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32)

Copia la totalidad de ReadOnlyCollectionBase en una matriz Array unidimensional compatible, comenzando en el índice especificado de la matriz de destino.Copies the entire ReadOnlyCollectionBase to a compatible one-dimensional Array, starting at the specified index of the target array.

ICollection.IsSynchronized ICollection.IsSynchronized ICollection.IsSynchronized ICollection.IsSynchronized

Obtiene un valor que indica si el acceso a un objeto ReadOnlyCollectionBase está sincronizado (es seguro para la ejecución de subprocesos).Gets a value indicating whether access to a ReadOnlyCollectionBase object is synchronized (thread safe).

ICollection.SyncRoot ICollection.SyncRoot ICollection.SyncRoot ICollection.SyncRoot

Obtiene un objeto que se puede utilizar para sincronizar el acceso a un objeto ReadOnlyCollectionBase.Gets an object that can be used to synchronize access to a ReadOnlyCollectionBase object.

Métodos de extensión

Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable)

Convierte los elementos de IEnumerable en el tipo especificado.Casts the elements of an IEnumerable to the specified type.

OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable)

Filtra los elementos de IEnumerable en función de un tipo especificado.Filters the elements of an IEnumerable based on a specified type.

AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable)

Habilita la paralelización de una consulta.Enables parallelization of a query.

AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable)

Convierte una interfaz IEnumerable en IQueryable.Converts an IEnumerable to an IQueryable.

Se aplica a

Seguridad para subprocesos

Los miembros estáticos públicos (Shared en Visual Basic) de este tipo son seguros para subprocesos.Public static (Shared in Visual Basic) members of this type are thread safe. No se garantiza que los miembros de instancias sean seguros para la ejecución de subprocesos.Any instance members are not guaranteed to be thread safe.

Esta implementación no proporciona un contenedor sincronizado (seguro para subprocesos) ReadOnlyCollectionBasepara un, pero las clases derivadas pueden crear sus propias versiones ReadOnlyCollectionBase sincronizadas SyncRoot de mediante la propiedad.This implementation does not provide a synchronized (thread safe) wrapper for a ReadOnlyCollectionBase, but derived classes can create their own synchronized versions of the ReadOnlyCollectionBase using the SyncRoot property.

Enumerar una colección no es intrínsecamente un procedimiento seguro para subprocesos.Enumerating through a collection is intrinsically not a thread-safe procedure. Incluso cuando una colección está sincronizada, otros subprocesos todavía pueden modificarla, lo que hace que el enumerador produzca una excepción.Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. Con el fin de garantizar la seguridad para la ejecución de subprocesos durante la enumeración, se puede bloquear la colección durante toda la enumeración o detectar las excepciones resultantes de los cambios realizados por otros subprocesos.To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.

Consulte también: