event-validation

EventValidation - Missing __EventValidation value in few requests

We have a textbox inside an update panel and it postsback on text change. Around 1 in 1000 POST request to server is missing the __EventValidation form element ( we verified using the logs that, when this exception occured the request was missing this form element ) As this is not happening consistently, we are ruling out any coding iss...

Invalid postback or callback argument

This question seems to have been asked before, but I feel like my situation is slightly different. I have a page that contains a gridview. When a button is pressed to edit one of the records in the gridview, the button first executes some client script that pops up a modal window for the purposes of editing (set using .onClientClick)...