单项选择题
A. Inherit the control class from the DependencyObject class.
B. Register a dependency property. In the options settings of the property metadata, specify the Inherits option.
C. Declare a new property. In the get and set methods of the new property, create an instance of the TraversalRequest class.
D. Declare a new property. In the get method of the new property call VisualTreeHelper.GetParent. In the set method of the new property, call VisualTreeHelper.GetChild.
单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You create a custom control named Wheel. You need to ensure that the Speed property of Wheel can be animated. What should you do?（）
单项选择题 You use Microsoft .NET Framework 4 to create a Windows application that can execute on client computers that run Windows Vista. You are creating a User Account Control (UAC) application manifest for the application. You need to ensure that users who are members of the local Administrators group do not receive a UAC prompt when the application executes. Which code fragment should you use? （）
单项选择题 You use Microsoft .NET Framework 4 to create a Windows Forms application. The application includes a RichTextBox control and a ListBox control. The ListBox control is populated with a list of valid file names. The application allows users to drag a ListBox item to the RichTextBox control. You need to provide a visual indication that a file that is dragged can be dropped on the RichTextBox control. What should you do?（）