How to tell what is passed when no value exists
<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>
