ToolStripControlHost.OnUnsubscribeControlEvents(Control) 方法
定义
重要
一些信息与预发行产品相关,相应产品在发行之前可能会进行重大修改。 对于此处提供的信息,Microsoft 不作任何明示或暗示的担保。
向托管控件取消订阅事件。
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)
参数
- control
- Control
向其取消订阅事件的控件。
示例
下面的代码示例演示如何取消订阅托管控件公开的事件。 此代码示例是为类提供的大型示例的 ToolStripControlHost 一部分。
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
注解
重写方法 OnUnsubscribeControlEvents 以取消订阅订阅中 OnSubscribeControlEvents订阅的事件。
引发事件时,将通过委托调用事件处理程序。 有关详细信息,请参阅 处理和引发事件。
OnUnsubscribeControlEvents 方法还允许派生类对事件进行处理而不必附加委托。 这是在派生类中处理事件的首选技术。
继承者说明
在派生类中重写 OnUnsubscribeControlEvents(Control) 时,一定要调用基类的 OnUnsubscribeControlEvents(Control) 方法,以便已注册的委托对事件进行接收。