CollectionBase.OnRemove Method

Performs additional custom processes when removing an element from the CollectionBase instance.

Namespace:  System.Collections
Assembly:  mscorlib (in mscorlib.dll)

abstract OnRemove : 
        index:int * 
        value:Object -> unit  
override OnRemove : 
        index:int * 
        value:Object -> unit

Parameters

index
Type: System.Int32

The zero-based index at which value can be found.

value
Type: System.Object

The value of the element to remove from index.

The default implementation of this method is intended to be overridden by a derived class to perform some action before the specified element is removed.

The On* methods are invoked only on the instance returned by the List property, but not on the instance returned by the InnerList property.

If the process fails, the collection reverts back to its previous state.

The default implementation of this method is an O(1) operation.

Notes to Implementers

This method allows implementers to define processes that must be performed before removing the element from the underlying System.Collections.ArrayList. By defining this method, implementers can add functionality to inherited methods without having to override all other methods.

OnRemove is invoked before the standard Remove behavior, whereas OnRemoveComplete is invoked after the standard Remove behavior.

For example, implementers can prevent removal of elements by always throwing an exception in OnRemove.

OnValidate is called prior to this method.

The following code example implements the CollectionBase class and uses that implementation to create a collection of Int16 objects.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Was this page helpful?
(1500 characters remaining)
Thank you for your feedback
Show:
© 2014 Microsoft