title: Searching for controls in Request.Form / Parsing a NameValueCollection
body: <p>I am searching for control names using Request.Form.</p>
  
  <p>Of course I know you can can iterate around all values using AllKeys, and you can do Form["controlName"] as well.</p>
  
  <p>However some of my control names are dynamic and it would be useful to be able to do stuff like:</p>
  
  <p>1)Getting a subset of controls in the collection whos name start with a certain prefix
  2) Search for control names that match a pattern, as you would do with a regular expression.</p>
  
  <p>But there is no way I can see to do stuff like this.</p>
  
  <p>N.B I know how to use FindControl for ASP.NET controls but these are standard HTML.</p>