TreeView.OnBeforeExpand Method (TreeViewCancelEventArgs)


Raises the BeforeExpand event.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

protected virtual void OnBeforeExpand(
	TreeViewCancelEventArgs e


Type: System.Windows.Forms.TreeViewCancelEventArgs

A TreeViewCancelEventArgs that contains the event data.

Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.

The OnBeforeExpand method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors:

When overriding OnBeforeExpand in a derived class, be sure to call the base class's OnBeforeExpand method so that registered delegates receive the event.

.NET Framework
Available since 1.1
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