title: How to tell what is passed when no value exists
body: <p>For this code, how do you know that null is returned if there is no value in the querystring?</p>
  
  <pre><code>HttpContext context = HttpContext.Current;
  string strValue = context.Request[name];
  </code></pre>
  
  <p>I'm asking because I never know what's being returned in many cases in the .NET framework when you don't get the value expected when it does not exist.</p>
  
  <p>so if <code>context.Request[name];</code> is called and the name doesn't exist in the querystring, how do you know it returns null or an empty string so that I can properly handle the case where it does not exist?</p>