How do I simulate a Tab key press when Return is pressed in a WPF application?

    protected override bool ProcessDialogKey(Keys keyData)
    {
        System.Diagnostics.Debug.WriteLine(keyData.ToString());

        switch (keyData)
        {
            case Keys.Enter:
                SendKeys.Send("{TAB}");
                break;
        }
        base.ProcessDialogKey(keyData);
        return false;
    }

How about make SendKeys Class Working like Winforms.SendKeys

https://michlg.wordpress.com/2013/02/05/wpf-send-keys/

public static class SendKeys
{
    public static void Send(Key key)
    {
        if (Keyboard.PrimaryDevice != null) {
            if (Keyboard.PrimaryDevice.ActiveSource != null) {
                var e1 = new KeyEventArgs(Keyboard.PrimaryDevice, Keyboard.PrimaryDevice.ActiveSource, 0, key) { RoutedEvent = Keyboard.KeyDownEvent };
                InputManager.Current.ProcessInput(e1);
            }
        }
    }
}

I think you should use that to simulate TAB :

SendKeys.Send("{TAB}");

Instead of

e.Key = Key.Tab

Sources : http://msdn.microsoft.com/en-us/library/system.windows.forms.sendkeys.send.aspx

You can look at a post here: http://social.msdn.microsoft.com/Forums/en/wpf/thread/c85892ca-08e3-40ca-ae9f-23396df6f3bd

Here's an example:

private void textBox1_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Enter)
            {
                TraversalRequest request = new TraversalRequest(FocusNavigationDirection.Next);
                request.Wrapped = true;
                ((TextBox)sender).MoveFocus(request);
            }
        }