Blogger Widgets
  • Sharing Photos using SignalR
  • TFS Extenstion - allows copy work items between projects
  • Displaying jquery progressbar with ajax call on a modal dialog
  • Managing windows services of a server via a website
  • Exploring technologies available to date. TechCipher is one place that any professional would like to visit, either to get an overview or to have better understanding.

Search This Blog

Tuesday, 26 October 2010

Invalid postback or callback argument on Post back

One of the most familiar error while working on ASP.NET ajax update panels is :-

505|error|500|Invalid postback or callback argument. Event validation is enabled using in configuration or in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.

Well its not quite easy and literally its frustrating to find out the cause. Everything is working fine in IE but not on firefox, chrome etc. So what went wrong is something very simple no one would expect.

Loading a webpage that contains number of user controls and one of which has a dropdown. The dropdown is binded to an array of strings. Now who would expect binding a string array to drop down would go wrong, no one but it does go wrong.

One of the string has a "\r" character which was messing the complete postback. Some how this is handled in IE but not on other browsers.

Any way after investing so much and finding so little to fix was a relief.

It has become appallingly obvious that our technology has exceeded our humanity.

~Albert Einstein


  1. I have to tell you that I was about to pull my hair out until I found this post. I have an updatepanel inside an iframe with a dropdownlist of addresses. The iframe is for sending a text message and my address object had "\r" in the dropdown value as an attempt at newlines in the sent text message. I had tried everything from registering the control for validation in the render method to switching to a regular select element. This worked for me, thanks so much!

  2. Good article.I really think what you said is right,in modern society,we have so many troubles,if you feel nothing to relax yourself,I suggest you to play the wow and some other games,and you can come to my page to find more information about http// and


Copyright © 2013 Template Doctor . Designed by Malith Madushanka - Cool Blogger Tutorials | Code by CBT | Images by by HQ Wallpapers