void Clear()
        {
            OnKeyPress(KeyboardSpecialKey.Clear);

            Output.Remove(0, Output.Length);
            OutputFeedback.FireUpdate();
        }
 /// <summary>
 ///
 /// </summary>
 /// <param name="s"></param>
 public void Press(string s)
 {
     OnKeyPress(s);
     Output.Append(s);
     OutputFeedback.FireUpdate();
     ResetShift();
 }
 /// <summary>
 ///
 /// </summary>
 /// <param name="c"></param>
 public void Press(char c)
 {
     OnKeyPress(c.ToString());
     Output.Append(c);
     OutputFeedback.FireUpdate();
     ResetShift();
 }
        void Backspace()
        {
            OnKeyPress(KeyboardSpecialKey.Backspace);

            if (Output.Length > 0)
            {
                Output.Remove(Output.Length - 1, 1);
                OutputFeedback.FireUpdate();
            }
        }