单项选择题
A.Call the Invoke method of the delegate.
B.Call the BeginInvoke and EndInvoke methods of the delegate in the calling thread.
C.Call the BeginInvoke method by specifying a callback method to be executed when the delegate is complete.Call the EndInvoke method in the callback method.
D.Call the BeginInvoke method by specifying a callback method to be executed when the delegate is complete.Call the EndInvoke method of the delegate in the calling thread.
单项选择题 YouarecreatingaWindowsFormsapplicationbyusingthe.NETFramework3.5.Youcreateanewforminyourapplication.Youadd100controlsatruntimeintheLoadeventhandleroftheform.Usersreportthattheformtakesalongtimetogetdisplayed.Youneedtoimprovetheperformanceoftheform.Whatshouldyoudo？（）
单项选择题 You are creating a Windows Forms application for a financial service provider by using the .NET Framework 3.5. You have to implement a multiple document interface （MDI） in the application to allow users to open multiple financial documents simultaneously.You need to ensure that whenever the child MDI form is created， the application displays a message in the title bar of the parent MDI that a child form has received focus. What should you do？（）
多项选择题 YouarecreatingaWindowsFormsapplicationbyusingthe.NETFramework3.5.TheapplicationdisplaysemployeenamesbyusingtheTreeViewcontrol.YouneedtoimplementthedraganddropfunctionalityintheTreeViewcontrol.Whichtwoactionsshouldyouperform？（）