title: Using double.Parse with a null value
body: <p>Below is my statement:</p>
  
  <pre><code>double? My_Value = null;
     if (Request.Form["MyValue"] != null)
      My_Value = double.Parse(Request.Form["MyValue"].ToString());
  </code></pre>
  
  <p>When I try to submit my form with no value for 'MyValue' I get a run time error saying 'Input string was not in a correct format.'. When I try to use:</p>
  
  <pre><code> My_Value = double.TryParse(Request.Form["MyValue"].ToString());
  </code></pre>
  
  <p>Visual Studio gives me a compile error that says 'No overload for method 'TryParse' takes 1 arguments'.</p>
  
  <p>When I provide a value for 'My_Value', the form submits.  How do I get the program to accept a null value?  Thank you.</p>