TreeView.OnBeforeExpand(TreeViewCancelEventArgs) Method
Definition
Important
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Raises the BeforeExpand event.
protected:
virtual void OnBeforeExpand(System::Windows::Forms::TreeViewCancelEventArgs ^ e);protected virtual void OnBeforeExpand (System.Windows.Forms.TreeViewCancelEventArgs e);abstract member OnBeforeExpand : System.Windows.Forms.TreeViewCancelEventArgs -> unit
override this.OnBeforeExpand : System.Windows.Forms.TreeViewCancelEventArgs -> unitProtected Overridable Sub OnBeforeExpand (e As TreeViewCancelEventArgs)Parameters
A TreeViewCancelEventArgs that contains the event data.
Remarks
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(TreeViewCancelEventArgs) in a derived class, be sure to call the base class's OnBeforeExpand(TreeViewCancelEventArgs) method so that registered delegates receive the event.
