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OnClear Method

CollectionBase.OnClear Method

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

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

'Declaration
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 Implementers

This method allows implementers to define processes that must be performed before deleting all the elements from the underlying System.Collections.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.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0
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