title: Extend the timer duration while ticking
body: <p>I have a windows form application with time input(in minutes) which fires a GUI application after the timer elapses. Initially I take the input from the user and set the time. Say, the user enters 45 mins. After 45 mins, my other GUI application is launched. Currently I'm using this:</p>
  
  <pre><code>Timer MyTimer = new Timer();
  
  private void Form1_Load(object sender, EventArgs e)
  {
      MyTimer.Interval = 45mins // Input from user
      MyTimer.Tick += new EventHandler(MyTimer_Tick);
      MyTimer.Start();
  }
  
  private void MyTimer_Tick(object sender, EventArgs e)
  {
      //pop my GUI application
  }
  </code></pre>
  
  <p>so now, my question is, how can i extended the timer? Suppose while counting down in the 20th Minute, the user wishes to extend 15mins of the timer, i take the input as 15 from the user and after that, the timer should add this 15 mins to the existing time and fire the GUI app after 35mins. i.e, it should count from 35mins.In total after the time elapses, it would have been 50mins. How can I achieve this?</p>