ASP.NET UpdatePanel为Repeater按钮抛出“Invalid Postback”异常

I have a simple repeater inside of an UpdatePanel that contains a label and two image buttons. The OnClick property is set in the attributes of each button at design time. When I click either of the buttons, I recieve the "Invalid postback or callback argument. Event validation is enabled........". I have done the exact same thing in other web applications but I cant seem to figure out whats going on here. I have a simple repeater inside of an UpdatePan