单项选择题 You are developing WPF application for managing student information... btnSort and a DataGrid control named dgStudents on the design surface of the MainWindow.xaml properties : FirstName and LastName. You create the following code segment in the constructor of... The DataGrid control displays the list of students unsorted. You need to ensure that the list of students is sorted by last name. Which code segment should you add to the click event handler of the Button control？（）

单项选择题 You need to ensure that phone numbers are displayed in the following format : (###) ### - ### Which markup segment should you use ?（）

单项选择题 When the application si run, it appears as follows You need to ensure that the TextBlock control with the contents "Product shipped" is horizontal centered to the grid? Which mark up segment should you add to the TextBlock control?（）