Cryptic errormessage from asp.net ajax updatepanel?

Where to fix this errormessage?

41|error|500|Input string was not in a correct forma开发者_如何学运维t.|

I'm confused

looks like server 500 error, line 41, with error message "Input string was not in a correct format", best to debug and break on all errors, assuming you are using VS you will break on the line of question

Input string was not in a correct format is typically an invalid integer cast somewhere. Make sure in your update panel you're not sending an improper string to an integer cast.