OK to throw an error for a missing required querystring parameter?
<p>Is there anything wrong with having an asp.net page throw a (custom error) if a a required querystring parameter is missing and having global.asax catch it with Application_Error, then transfer the user to an error page?  I have several base classes that perform these checks and I am not sure of the best way to communicate the error to a user. </p>

<p>So, something like this:</p>

<pre><code>int reqParam;
if(!isParamSet("myReqParam", out reqParam))
{
   throw new QuerystringParamMissingException();
}
</code></pre>

<p>which is then caught by Application_Error in global.asax.</p>

<p>Also, from a security standpoint how much information should I be providing to the user?  Just that it was an error, or that a querystring parameter was missing, or which parameter was missing, or maybe even what that parameter indicates is used for?</p>
