Invalid postback or callback argument on Post back

One of the most familiar error while working on ASP.NET ajax update panels is :-

505|error|500|Invalid postback or callback argument. Event validation is enabled using in configuration or in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.



Well its not quite easy and literally its frustrating to find out the cause. Everything is working fine in IE but not on firefox, chrome etc. So what went wrong is something very simple no one would expect.

Loading a webpage that contains number of user controls and one of which has a dropdown. The dropdown is binded to an array of strings. Now who would expect binding a string array to drop down would go wrong, no one but it does go wrong.

One of the string has a "\r" character which was messing the complete postback. Some how this is handled in IE but not on other browsers.

Any way after investing so much and finding so little to fix was a relief.

It has become appallingly obvious that our technology has exceeded our humanity.

~Albert Einstein