Invalid postback or callback argument.

All out of sudden I have the following error (on page with grid view) though the page was working just fine before.

“Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation=”true” %> in a page…

I googled and as far as I can find there are two ways to fix it..
1. put unique IDs to your image buttons (I use image button in my gridview)
2. disable event validation

But I really don’t like none of those fiex because it looks a bit lame to me (I might be wrong).

So, I looked into my code again. Because the page was working fine before I change something (put a user control with repeater inside). So I carefully check my user control code and found out I bind the repeater regardless of postback state (bad bad coding :/) So I fixed my user control to bind only on not postback and WHAM! it works.

Displaying Many-To-Many Relations In Repeater

I’ve wasted a lot of time thinking of how to do that. Well it is so simple, just tell not to put constraints (bool constraints = false) when adding relations to data source.