TreeView.OnBeforeCollapse(TreeViewCancelEventArgs) Method
Definition
Important
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Raises the BeforeCollapse event.
protected:
virtual void OnBeforeCollapse(System::Windows::Forms::TreeViewCancelEventArgs ^ e);protected public:
virtual void OnBeforeCollapse(System::Windows::Forms::TreeViewCancelEventArgs ^ e);protected virtual void OnBeforeCollapse (System.Windows.Forms.TreeViewCancelEventArgs e);protected internal virtual void OnBeforeCollapse (System.Windows.Forms.TreeViewCancelEventArgs e);abstract member OnBeforeCollapse : System.Windows.Forms.TreeViewCancelEventArgs -> unit
override this.OnBeforeCollapse : System.Windows.Forms.TreeViewCancelEventArgs -> unitProtected Overridable Sub OnBeforeCollapse (e As TreeViewCancelEventArgs)Protected Friend Overridable Sub OnBeforeCollapse (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 OnBeforeCollapse 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 OnBeforeCollapse(TreeViewCancelEventArgs) in a derived class, be sure to call the base class's OnBeforeCollapse(TreeViewCancelEventArgs) method so that registered delegates receive the event.
