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?（）
A. Use a DoubleAnimation class.
B. Use a Storyboard animation class.
C. Use the DragDropEffects enumeration.
D. Use the DragAction enumeration.
相关考题
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单项选择题
You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application uses the drag-and-drop functionality. You need to ensure that the drag-and-drop operation is stopped when a user moves the cursor outside the boundaries of the application form. Which enumeration member should you use?（）
A. DragAction.Cancel
B. DragAction.Drop
C. DragDropEffects.None
D. DragDropEffects.All -
多项选择题
You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application uses the background worker process (BWP). When the user clicks a button, the background worker executes a method named DoCalculations asynchronously. You need to implement a progress bar on the user interface (UI) that informs the user of the progress of DoCalculations. Which two actions should you perform?（）
A. Modify the Value property of the progress bar in DoCalculations.
B. Modify the Value property of the progress bar in the ProgressChanged event handler of the background worker.
C. Modify the Value property of the progress bar in the RunWorkerCompleted event handler of the background worker.
D. Call the ReportProgress method of the background worker in DoCalculations.
E. Call the ReportProgress method of the background worker in the DoWork event handler of the background worker. -
单项选择题
You use Microsoft .NET Framework 4 to create an application. The application performs resource-intensive calculations that consist of multiple layers of nested looping. The application will be deployed to servers that contain varying hardware configurations. You need to ensure that the application utilizes CPU resources on the server in the most efficient manner. You want to achieve this goal by using the minimum amount of code. What should you do?（）
A. Use multiple System.Threading.Thread objects.
B. Use the background worker process (BWP).
C. Use the Thread.BeginInvoke method.
D. Use the Parallel.For method.
