单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You create a window that contains a Button control and a MenuItem control. Both controls are labeled "Add sugar." The Command properties of the Button and MenuItem controls are set to the same RoutedCommand named AddSugarCommand. You write the following code segment. private void CanAddSugar (object sender, CanExecuteRoutedEventArgs e) { ... } You need to ensure that when the CanAddSugar method sets e.CanExecute to false, the MenuItem and Button controls are disabled. What should you do?（）

多项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application contains a composite user control that includes a TextBox control named txtInput. The user control will be hosted in a window and will have handlers for the text-changed event of txtInput. You need to ensure that the application meets the following requirements: AddHandler(TextBox.TextChangedEvent, new RoutedEventHandler(Audit_TextChanged), true); Which of the following statments are TRUE ?（）

单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application contains a composite user control that includes a TextBox control named txtInput. The user control will be hosted in a window and will have handlers for the text-changed event of txtInput. You need to ensure that the application meets the following requirements: Creates a text-changed event handler named Audit_TextChanged for the txtInput control. Executes Audit_TextChanged even when specific handlers mark the event as handled. Which code segment should you add to the constructor of the user control?（）