单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. You want to add an audio player that plays .wav or .mp3 files when the user clicks a button. You plan to store the name of the file to a variable named SoundFilePath. You need to ensure that when a user clicks the button, the file provided by SoundFilePath plays. What should you do?（）

单项选择题 You create a Windows client application by using Windows Presentation Foundation (WPF). The application contains the following code fragment. You need to assign lbDetails to use the detail data template when btnDetails is clicked. Which code segment should you write for the click event handler for btnDetails?（）

单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application has a window named MainWindow that has a StackPanel control named sp as the root element. You want to create a Button control that contains a TextBlock control with the "Save" Text property. You need to create the control dynamically and add the control to sp. Which code segment should you write in the constructor of the MainWindow class?（）