ASP.NET error checking

As a general rule of thumb you should put all your code in Try..Catch block. I tell you the advantage of this approach. When you are developing the application, you will always run/test it in a such way that it does not crash, It is a natural human tendency. But when the same code is deployed on Client Site, he will run it in the worst case he can. In order to avoid your module crashing, it is advisable that you put your code in Try..Catch Block. For user control as well this rule remains the same.

But in the catch block you can log this error. You can log the error in Eventviewer, Text File etc. so that at a later time you can have a look at the situation which lead to this error. You can use Microsoft Logging Application Block, NLog etc frameworks for logging purpose.

Hope this helps.
All the best.