#1,069 – Main Window Initially Has Keyboard Focus

When you first start a WPF application which contains elements that can get keyboard focus (e.g. TextBox), it’s the main Window that has the keyboard focus when the application starts.

We can see this by using code that reports the current keyboard focus within a Label at the bottom of the window.

If we attach an event handler to the main Window for the TextInput event and use the handler to log information about the event, we can start typing after the window comes up and see that the Window is getting TextInput events based on what we type.  Nothing is rendered to the screen, but our logging indicates that TextInput events are being fired, with the main window as their source.

        private void Window_TextInput(object sender, TextCompositionEventArgs e)
        {
            Trace.WriteLine(string.Format("Window_TextInput: [{0}], source={1}", e.Text, e.Source.ToString()));
        }