To set a Window's Default button
Set your default button's IsDefault property to true.
Note that you can also set a Window's Cancel button by setting a button's IsCancel property to true.
To set the Selected (focused) button in a Window
If you want to select a particular button then use the Focus method like this:
yourButton.Focus();
You might do this when a Window loads (in the Window_Loaded event).
To select a particular button when your Window opens make sure its IsTabStop property is set to true and ensure its TabIndex property is lower than any other control on the Window.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…