Beginning ASP.NET 3.5 in C# 2008: From Novice to Professional, Second Edition

25.3. Progress Notification

As you've learned, the UpdatePanel performs its work asynchronously in the background. As a result, the user can keep working with the page. This is generally the behavior you want, but there's one catch. While the asynchronous request is under way, the user won't necessarily realize that anything's happening. If the asynchronous request takes some time, this could be a bit of a problem. At worst, the user will assume the page is broken or click the same button multiple times, creating needless extra work for your web application and slowing down the process further.

ASP.NET includes another control that can help—the UpdateProgress control. The UpdateProgress control works in conjunction with the UpdatePanel. Essentially, ...