ASP.NET 1316 event



I am not sure if this is the right place to raise this issue. I am posting to this forum because the malfunctioning components are WCSF based.

We have a web application which shows dashboards to users. An ASPX webpage in this application represents a dashboard. This web page is derived from 'Microsoft.Practices.CompositeWeb.Web.UI.Page'. The dashboard can contain multiple panels. These panels are usercontrols derived from 'Microsoft.Practices.CompositeWeb.Web.UI.UserControl'.

When I add a tabular panel to the dashboard, I get a server side exception upon post-back. Here are the details of the exception and call stack.

"An unhandled exception occured during execution of web request 'http://localhost/CCS_Web/DynamicDashboard/ViewDashboard.aspx?mod=DynamicDashboard&view=ViewDashboard&IsDashboardTabSelected=True&GUID=89c096ea-9f92-4f17-8473-ecdba9fab852'. : System.FormatException: The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or a non-white space character among the padding characters.
at System.Convert.FromBase64String(String s)
at System.Web.UI.ObjectStateFormatter.Deserialize(String inputString)
at System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter.Deserialize(String serializedState)
at System.Web.UI.Util.DeserializeWithAssert(IStateFormatter formatter, String serializedState)
at System.Web.UI.HiddenFieldPageStatePersister.Load()"

A Tabular panel is actually 'asp:gridview' behind the scene.

Attached is the event I am seeing in the web server event viewer.

My observation is that whenever I add a tabular panel, I see two viewstate variables with same name '__Viewstate' in the IE Dev Tools view. And in the fiddler, I see these two viewstates going back to server separated by comma between them.

I can assure that we are not doing any custom viewstate manipulation behind the scene.

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