We are getting the error below when a customer tries to remove a promotion code from his cart by clicking on the X button.

Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> 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.[ at System.Web.UI.ClientScriptManager.ValidateEvent(String uniqueId, String argument) at System.Web.UI.Control.ValidateEvent(String uniqueID, String eventArgument) at System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) at System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) ]

Please let me know if you need more details on this, but it seems to me that this is a generic 5.4 error and can easily be replicated.

Can Agaoglu
The Araca Group

I'm running 5.4 rev 5 with all the hot fixes installed. No customizations. Can you recall which hot fix it was that took care of this?

Nope, I did not customize anything on this page. I get the same error for our websites that are untouched fresh installs.

Version Information: Microsoft .NET Framework Version:2.0.50727.1433; ASP.NET Version:2.0.50727.1433

Okay, let me add it to the list of things to investigate. Any special coupon type or setup that I should need to be aware of to duplicate this?

Hi,
I too have had this problem.
Actually in the file cart.aspx we have the same problem solved long ago.

Code wrong:
&lt;asp: GridView cellpadding = "3" cellspacing = "0" gridlines = "none" ID = "CouponGrid" runat = "server"
AutoGenerateColumns = "False" DataKeyNames = "CouponCode" ShowHeader = "False"&gt;


Code exact:
&lt;asp: GridView EnableViewState = "false" cellpadding = "3" cellspacing = "0" gridlines = "none" ID = "CouponGrid" runat = "server"
AutoGenerateColumns = "False" DataKeyNames = "CouponCode" ShowHeader = "False"&gt; "


Code different:
EnableViewState = "false".



Antonio