EventValidation - Missing __EventValidation value in few requests

Question

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 issues. We suspect the user is posting the form even before the form is completely loaded.

---

Question: Is it ok, to move this __EventValidation element to the top section of the form instead of bottom if we are not doing any Response.Flush by overriding the Render method?

Answer 1

It looks like the .NET 2.0 SP2 has this fixed.

http://blogs.msdn.com/tom/archive/2008/03/14/validation-of-viewstate-mac-failed-error.aspx#8970568