CollectionBase.OnClear Method


Performs additional custom processes when clearing the contents of the CollectionBase instance.

 virtual void OnClear();
protected virtual void OnClear ();
abstract member OnClear : unit -> unit
override this.OnClear : unit -> unit
Protected Overridable Sub OnClear ()


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

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 Inheritors

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

OnClear() is invoked before the standard Clear behavior, whereas OnClearComplete() is invoked after the standard Clear behavior.

For example, implementers can exempt certain elements from deletion by a global Clear.

Applies to

See also