title: Get a DateTime by subtracting seconds from the current date
body: <p>I would like to subtract seconds from a date, for example:</p>
  
  <p>Lets say I have 1300 seconds in a unsigned integer, I would like to take the current date and time, subtract 1,300 seconds from it, and end up with:</p>
  
  <p><code>01/13/2012 2:15 PM</code> (format doesn't really matter).</p>
  
  <p>I did try: </p>
  
  <pre><code>DateTime dt = new DateTime(); 
  dt.Add(new TimeSpan(0, 0, ui.OnlineTime)); 
  Online.Text = dt.ToLongDateString();
  </code></pre>