How to display an error message box in a web application asp.net c#

Question

I have an ASP.NET web application, and I wanted to know how I could display an error message box when an exception is thrown.

For example,

Answer 1

I wouldn't think that you would want to show the details of the exception. We had to stop doing this because one of our clients didn't want their users seeing everything that was available in the exception detail. Try displaying a javascript window with some information in it explaining that there has been a problem.