ToolStripControlHost.OnUnsubscribeControlEvents(Control) Method

Reference

Definition

Namespace:: System.Windows.Forms

Assembly:: System.Windows.Forms.dll

Important

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Unsubscribes events from the hosted control.

protected:
 virtual void OnUnsubscribeControlEvents(System::Windows::Forms::Control ^ control);

protected virtual void OnUnsubscribeControlEvents (System.Windows.Forms.Control control);

protected virtual void OnUnsubscribeControlEvents (System.Windows.Forms.Control? control);

abstract member OnUnsubscribeControlEvents : System.Windows.Forms.Control -> unit
override this.OnUnsubscribeControlEvents : System.Windows.Forms.Control -> unit

Protected Overridable Sub OnUnsubscribeControlEvents (control As Control)

Parameters

control: Control

The control from which to unsubscribe events.

Examples

The following code example demonstrates how to unsubscribe from an event exposed by the hosted control. This code example is part of a larger example provided for the ToolStripControlHost class.

void OnUnsubscribeControlEvents( System::Windows::Forms::Control^ c )
{
   
   // Call the base method so the basic events are unsubscribed.
   __super::OnUnsubscribeControlEvents( c );
   
   // Cast the control to a MonthCalendar control.
   MonthCalendar^ monthCalendarControl = (MonthCalendar^)c;
   
   // Remove the event.
   monthCalendarControl->DateChanged -= gcnew DateRangeEventHandler( this, &ToolStripMonthCalendar::HandleDateChanged );
}

protected override void OnUnsubscribeControlEvents(Control c)
{
    // Call the base method so the basic events are unsubscribed.
    base.OnUnsubscribeControlEvents(c);

    // Cast the control to a MonthCalendar control.
    MonthCalendar monthCalendarControl = (MonthCalendar) c;

    // Remove the event.
    monthCalendarControl.DateChanged -=
        new DateRangeEventHandler(OnDateChanged);
}

Protected Overrides Sub OnUnsubscribeControlEvents(ByVal c As Control)
    ' Call the base method so the basic events are unsubscribed.
    MyBase.OnUnsubscribeControlEvents(c)

    ' Cast the control to a MonthCalendar control.
    Dim monthCalendarControl As MonthCalendar = _
        CType(c, MonthCalendar)

    ' Remove the event.
    RemoveHandler monthCalendarControl.DateChanged, _
        AddressOf HandleDateChanged

End Sub

Remarks

Override the OnUnsubscribeControlEvents method to unsubscribe events subscribed in OnSubscribeControlEvents.

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

The OnUnsubscribeControlEvents 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 OnUnsubscribeControlEvents(Control) in a derived class, be sure to call the base class's OnUnsubscribeControlEvents(Control) method so that registered delegates receive the event.

Applies to

共用方式為