Did user use keyboard or mouse to leave WPF TextBox?

Question

I have a handler for the TextBox's PreviewLostKeyboardFocus event. It fires when I leave the TextBox using the keyboard (Tab key) or the mouse (by clicking on another TextBox on the form).

The handler takes a KeyboardFocusChangedEventArgs, which has a property named KeyboardDevice, which isn't null in either scenario (I was hoping to find null here when using the mouse).

Question: How can I tell whether a user used the keyboard or the mouse to leave a WPF TextBox?

Answer 1

The e.KeyboardDevice.GetKeyStates(Key.Tab) (where e is of type KeyboardFocusChangedEventArgs) reports:

• None (when mouse was used to change focus)
• Down, Toggled (when TAB was use to leave the TextBox)

Would that work for you?