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CollectionBase.OnInsert (Método)

Realiza procesos personalizados adicionales antes de insertar un nuevo elemento en la instancia de CollectionBase.

Espacio de nombres: System.Collections
Ensamblado: mscorlib (en mscorlib.dll)

protected virtual void OnInsert (
	int index,
	Object value
)
protected void OnInsert (
	int index, 
	Object value
)
protected function OnInsert (
	index : int, 
	value : Object
)

Parámetros

index

Índice de base cero en el que se va a insertar value.

value

Nuevo valor del elemento situado en index.

El propósito de la implementación predeterminada de este método es que sea reemplazada por una clase derivada que realice alguna acción antes de que se inserte el elemento especificado.

Los métodos On* sólo se invocan en la instancia devuelta por la propiedad List, pero no en la instancia devuelta por la propiedad InnerList.

Si se produce un error en el proceso, la colección vuelve a su estado anterior.

La implementación predeterminada de este método es una operación O(1).

Notas para los implementadores Este método permite a los implementadores definir procesos que deben ejecutarse antes de insertar el elemento en la clase System.Collections.ArrayList subyacente. Al definir este método, los implementadores pueden agregar funcionalidad a los métodos heredados sin tener que sustituir todos los demás métodos. El método OnInsert se invoca antes del comportamiento estándar de Insert, mientras que el método OnInsertComplete se invoca después del comportamiento estándar de Insert. Por ejemplo, los implementadores pueden limitar qué tipos de objetos se pueden insertar en la clase System.Collections.ArrayList. Se llama al método OnValidate antes que a este método.

El siguiente ejemplo de código implementa la clase CollectionBase y utiliza dicha implementación para crear una colección de objetos Int16.

using System;
using System.Collections;

public class Int16Collection : CollectionBase  {

   public Int16 this[ int index ]  {
      get  {
         return( (Int16) List[index] );
      }
      set  {
         List[index] = value;
      }
   }

   public int Add( Int16 value )  {
      return( List.Add( value ) );
   }

   public int IndexOf( Int16 value )  {
      return( List.IndexOf( value ) );
   }

   public void Insert( int index, Int16 value )  {
      List.Insert( index, value );
   }

   public void Remove( Int16 value )  {
      List.Remove( value );
   }

   public bool Contains( Int16 value )  {
      // If value is not of type Int16, this will return false.
      return( List.Contains( value ) );
   }

   protected override void OnInsert( int index, Object value )  {
      // Insert additional code to be run only when inserting values.
   }

   protected override void OnRemove( int index, Object value )  {
      // Insert additional code to be run only when removing values.
   }

   protected override void OnSet( int index, Object oldValue, Object newValue )  {
      // Insert additional code to be run only when setting values.
   }

   protected override void OnValidate( Object value )  {
      if ( value.GetType() != typeof(System.Int16) )
         throw new ArgumentException( "value must be of type Int16.", "value" );
   }

}


public class SamplesCollectionBase  {

   public static void Main()  {
 
      // Create and initialize a new CollectionBase.
      Int16Collection myI16 = new Int16Collection();

      // Add elements to the collection.
      myI16.Add( (Int16) 1 );
      myI16.Add( (Int16) 2 );
      myI16.Add( (Int16) 3 );
      myI16.Add( (Int16) 5 );
      myI16.Add( (Int16) 7 );

      // Display the contents of the collection using foreach. This is the preferred method.
      Console.WriteLine( "Contents of the collection (using foreach):" );
      PrintValues1( myI16 );

      // Display the contents of the collection using the enumerator.
      Console.WriteLine( "Contents of the collection (using enumerator):" );
      PrintValues2( myI16 );

      // Display the contents of the collection using the Count property and the Item property.
      Console.WriteLine( "Initial contents of the collection (using Count and Item):" );
      PrintIndexAndValues( myI16 );

      // Search the collection with Contains and IndexOf.
      Console.WriteLine( "Contains 3: {0}", myI16.Contains( 3 ) );
      Console.WriteLine( "2 is at index {0}.", myI16.IndexOf( 2 ) );
      Console.WriteLine();

      // Insert an element into the collection at index 3.
      myI16.Insert( 3, (Int16) 13 );
      Console.WriteLine( "Contents of the collection after inserting at index 3:" );
      PrintIndexAndValues( myI16 );

      // Get and set an element using the index.
      myI16[4] = 123;
      Console.WriteLine( "Contents of the collection after setting the element at index 4 to 123:" );
      PrintIndexAndValues( myI16 );

      // Remove an element from the collection.
      myI16.Remove( (Int16) 2 );

      // Display the contents of the collection using the Count property and the Item property.
      Console.WriteLine( "Contents of the collection after removing the element 2:" );
      PrintIndexAndValues( myI16 );

   }
 
   // Uses the Count property and the Item property.
   public static void PrintIndexAndValues( Int16Collection 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( Int16Collection myCol )  {
      foreach ( Int16 i16 in myCol )
         Console.WriteLine( "   {0}", i16 );
      Console.WriteLine();
   }

   // Uses the enumerator. 
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintValues2( Int16Collection 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):
   1
   2
   3
   5
   7

Contents of the collection (using enumerator):
   1
   2
   3
   5
   7

Initial contents of the collection (using Count and Item):
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   5
   [4]:   7

Contains 3: True
2 is at index 1.

Contents of the collection after inserting at index 3:
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   13
   [4]:   5
   [5]:   7

Contents of the collection after setting the element at index 4 to 123:
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   13
   [4]:   123
   [5]:   7

Contents of the collection after removing the element 2:
   [0]:   1
   [1]:   3
   [2]:   13
   [3]:   123
   [4]:   7

*/


import System.* ;
import System.Collections.*;
import System.Collections.CollectionBase.*;

public class Int16Collection extends CollectionBase
{
    /** @property 
     */
    public short get_Value(int index)
    {
        short s = System.Convert.ToInt16(get_List().get_Item(index));
        return(s) ; 
    } //get_Value

    /** @property 
     */
    public void set_Value(int index,short value)
    {
        get_List().set_Item(index, (Int16)value);
    } //set_Value
   
    public int Add(short value) 
    {
        return get_List().Add((Int16)value);
    } //Add
   
    public int IndexOf(short value)
    {
        return get_List().IndexOf((Int16)value);
    } //IndexOf
     
    public void Insert(int index, short value) 
    {
        get_List().Insert(index, (Int16)value);
    } //Insert
   
    public void Remove(short value) 
    {
        get_List().Remove((Int16)value);
    } //Remove
   
    public boolean Contains(short value) 
    {
        // If value is not of type Int16, this will return false.
        return get_List().Contains((Int16)value);
    } //Contains
   
    protected   void OnInsert(int index, Object value) 
    {
        // Insert additional code to be run only when inserting values.
    } //OnInsert
    
       protected   void OnRemove(int index, Object value) 
    {
        // Insert additional code to be run only when removing values.
    } //OnRemove
    
       protected   void OnSet(int index, Object oldValue, Object newValue) 
    {
        // Insert additional code to be run only when setting values.
    } //OnSet
    
    protected   void OnValidate(Object value) 
    {
        if ( value.GetType() != Type.GetType("System.Int16")  ) {
            throw new ArgumentException("value must be of type Int16.", 
                "value");
        }
    } //OnValidate
} //Int16Collection

public class SamplesCollectionBase
{
    public static void main(String[] args)
    {
        // Create and initialize a new CollectionBase.
        Int16Collection myI16 =  new Int16Collection();
      
        // Add elements to the collection.
        myI16.Add((Int16)1);
        myI16.Add((Int16)2);
        myI16.Add((Int16)3);
        myI16.Add((Int16)5);
        myI16.Add((Int16)7);
          
        // Display the contents of the collection using for.
        Console.WriteLine("Contents of the collection (using for):");
        PrintValues1(myI16);
          
        // Display the contents of the collection using the enumerator.
        Console.WriteLine("Contents of the collection (using enumerator):");
        PrintValues2(myI16);
          
        // Display the contents of the collection using the Count property and 
        // the Item property.
        Console.WriteLine("Initial contents of the collection "
            + "(using Count and Item):");
        PrintIndexAndValues(myI16);
          
        // Search the collection with Contains and IndexOf.
        Console.WriteLine("Contains 3: {0}", 
            (System.Boolean)myI16.Contains((Int16)3));
        Console.WriteLine("2 is at index {0}.", 
            (Int16)myI16.IndexOf((Int16)2));
        Console.WriteLine();
          
        // Insert an element into the collection at index 3.
        myI16.Insert(3, (Int16)13);
        Console.WriteLine("Contents of the collection after inserting at"
            + " index 3:");
        PrintIndexAndValues(myI16);
          
        // Get and set an element using the index.
        myI16 .set_Item( 4 ,(Int16)123 );
        Console.WriteLine("Contents of the collection after setting the"
            + " element at index 4 to 123:");
        PrintIndexAndValues(myI16);
          
        // Remove an element from the collection.
        myI16.Remove((Int16)2);
          
        // Display the contents of the collection using the Count property and
        // the Item property.
        Console.WriteLine("Contents of the collection after removing the"
            + " element 2:");
        PrintIndexAndValues(myI16);
   } //main
    
   // Uses the Count property and the Item property.
    public static void PrintIndexAndValues(Int16Collection myCol) 
    {
        for(int i = 0; i < myCol.get_Count(); i++) {
            Console.WriteLine("   [{0}]:   {1}", (Int32)i, 
                myCol.get_Item(i));
        } 
        Console.WriteLine();
    } //PrintIndexAndValues
   
    // Uses the for statement which hides the complexity of the enumerator.
    // NOTE: The for statement is the preferred way of enumerating the contents 
    // of a collection.
    public static void PrintValues1(Int16Collection myCol) 
    {
        for (int iCtr = 0; iCtr < myCol.get_Count(); iCtr++) {
            Console.WriteLine("   {0}", myCol.get_Item(iCtr));
        }
        Console.WriteLine();
    } //PrintValues1
   
    // Uses the enumerator. 
    // NOTE: The for statement is the preferred way of enumerating the contents 
    // of a collection.
    public static void PrintValues2(Int16Collection myCol) 
    {
        System.Collections.IEnumerator myEnumerator = myCol.GetEnumerator();
        while(myEnumerator.MoveNext()) {
            Console.WriteLine("   {0}", myEnumerator.get_Current());
        }
        Console.WriteLine();
    } //PrintValues2
} //SamplesCollectionBase

/* 
Contents of the collection (using for):
   1
   2
   3
   5
   7

Contents of the collection (using enumerator):
   1
   2
   3
   5
   7

Initial contents of the collection (using Count and Item):
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   5
   [4]:   7

Contains 3: True
2 is at index 1.

Contents of the collection after inserting at index 3:
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   13
   [4]:   5
   [5]:   7

Contents of the collection after setting the element at index 4 to 123:
   [0]:   1
   [1]:   2
   [2]:   3
   [3]:   13
   [4]:   123
   [5]:   7

Contents of the collection after removing the element 2:
   [0]:   1
   [1]:   3
   [2]:   13
   [3]:   123
   [4]:   7

*/


Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium, Windows Mobile para Pocket PC, Windows Mobile para Smartphone, Windows Server 2003, Windows XP Media Center, Windows XP Professional x64, Windows XP SP2, Windows XP Starter Edition

.NET Framework no admite todas las versiones de cada plataforma. Para obtener una lista de las versiones admitidas, vea Requisitos del sistema.

.NET Framework

Compatible con: 2.0, 1.1, 1.0

.NET Compact Framework

Compatible con: 2.0, 1.0

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