title: ASP.Net excessive use of User Controls
body: <p>I'm investigating an asp.net web application that extensively uses User Controls on each page. Most pages contain around 10-20 user controls. The User controls seem to be the visual representation of the business objects (if that makes sense), although at a finer granularity such as each tab of a tab control having its contents in a user control. The project itself has over 200 user controls (ascx files).</p>
  
  <p>The performance of the application is very poor (and the reason I'm investigating). Each event (such as a click or dropdown selection etc) requires about 5 seconds for the page to load (10 seconds whilst in visual studio). The application has no use of Ajax.</p>
  
  <p>Tracing is painful as the aspx pages themselves have no code in the code-behind as the user controls look after all of this, so tracing a single page requires trace statements in all the user controls that are on that page.</p>
  
  <p>I actually think that having each user control look after its business code and being re-usable is a smart idea, but is an excessive use of user controls going to incur a performance hit? Does this seem like the structure of an asp.net application that was written by someone with a strong WinForms background?</p>
  
  <p><strong>EDIT</strong><br>
  thought I should add that i'm not questioning the use of user controls (or even the amount) but simply whether having so many on a page that all accomplish things (each user control connects to the database for example) will generally cause performance problems...For example, if just one user control postsback to do something, what about the processing of all the others, some are visible and some aren't...@David McEwing mentioned that he had 40 optimised user controls performing etc, but if the developer was WinForms based or "not familiar with asp.net", then how are they going to make sure each one is optimised...</p>
  
  <p><strong>EDIT2</strong><br>
  After getting a sql statement trace, the same calls for data are being executed 5-6 times per page call for each event as the different user controls require data that is not stored commonly e.g. each user control in the tab (mentioned above) makes the same call to populate an object from the database...I'm really not here to accuse user controls of being the problem (should i delete the question?) as clearly the problem is NOT user controls but with the use of them in this particular case...which I believe is excessive!</p>