单项选择题
A. Implement the INotifyPropertyChanged interface in the Product class.
B. Implement the INotifyCollectionChanged interface in the ProductList class.
C. Set the Mode property of the Binding object of the ListBox control to TwoWay.
D. Set the UpdateSourceTrigger property of the Binding object of the ListBox control to PropertyChanged.
单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You write the following code fragment. You need to implement the MyProject.AverageConverter class. What should you do?（）
单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You write the following code fragment. You need to implement the MyProject.MyConverter class. What should you do?（）
单项选择题 You use Microsoft Visual Studio 2010 and Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You write the following code fragment. You need to ensure that the StringMember property of the data-bound object is updated immediately when the user types the TextBox control. Which binding expression should you use?（）