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CollectionBase.OnClear Method

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

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

protected virtual void 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.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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