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?（）

单项选择题 You use Microsoft Visual Studio 2010 and Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application contains a ListBox control named lbxItems that is data-bound to a collection of objects. Each object has a DisplayValue property. You add a Button control to the application. You need to ensure that the Content property of the Button control is data-bound to the DisplayValue property of the selected item of lbxItems. Which binding expression should you use?（）