You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You write the following code fragment. (Line numbers are included for reference only.) 
You need to ensure that a video file begins to play only when a user clicks Play. Which code fragment should you insert at line 06?（）
- A、
- B、
- C、
- D、
正确答案:B
答案解析:有
微信扫一扫手机做题