Invalid postback or callback argument. Event validation is enabled
This error happens in the following situation.
When you modify Asp.Net controls from client side after page is completely loaded.
Then if you do a postback, you will get this error.
This is because, when page load happens, Asp.Net controls will get registered.
And the controls get validated when postback happens.
During postback validation, if any mismath happens, you will get this error.
This is a type of Asp.Net security that prevents any unauthorized postback requests.
On your Aspx page, set EnableEventValidation as false.
We strongly recommend not to disable EventValidation.
The best option is to use update panel for updating Asp.Net controls.
This would definitely allow you to update only a particular control.
As shown in the figure, we can use update panel in Aspx page and code behind.
If nothing works for you, then go with normal Server side postback for binding controls.
By this way you will definitely get validated on each callback.
This will definitely resolve your issue.