Invalid postback or callback argument. Event validation is enabled using ''

Question

I am getting the following error when I post back a page from the client-side. I have JavaScript code that modifies an asp:ListBox on the client side.

How do we fix

Answer 1

One other way not mentioned here is to subclass ListBox

Ie.

public class ListBoxNoEventValidation : ListBox 
{
}

ClientEventValidation keys off the attribute System.Web.UI.SupportsEventValidation if you subclass it, unless you explicitly add it back in, it will never call the validation routine. That works with any control, and is the only way I've found to "disable" it on a control by control basis (Ie, not page level).