You have to worry about session timeouts for applications where the user might take a long time.
You also have to worry about uploading timeouts for large applications, too
Validatiors may not always scroll your page to the scene of the data entry error (so the user may not ever see it and will only wonder why the submit button won't work )
If the user enters HTML symbols such as <, > (for example, P > 3.14 ), or an inadvertant
null.ToString() produces a big fat error. Check carefully.
Session pool sharing across multiple applications is a disaster silently waiting to happen
Moving applications around on machines with different environments is a migraine that involves web.config and many potential hours of google
ASP.NET and MySQL are prone to caching problems if you use stored procedures
AJAX can make a mess, too:
- There are situations where the client can bypass page validation (especially by pressing ENTER instead of pressing the submit button). You can fix it by calling
if(! Page.IsValid) { return ; }
- ASP buttons usually don't work correctly inside of UpdatePanels
- The more content in your UpdatePanel, the more data is asynchronously transmitted, so the longer it takes to load
- If your AJAX panel has a problem or error of some kind, it "locks up" and doesn't respond to events inside it anymore
