Viewstate error

Question

Hi! I am getting a viewstate error on the live site: Thanks on any advice

Inner Exception: System.Web.UI.ViewStateException: Invalid viewstate. Client IP: 111.34.19.201 Port: 54016 User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; GTB6; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30618) ViewState: 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... ---> System.FormatException: Invalid length for a Base-64 char array. 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() --- End of inner exception stack trace ---

Target Site: Void ThrowError(System.Exception, System.String, System.String, Boolean)

Stack trace: at System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) at System.Web.UI.ViewStateException.ThrowViewStateError(Exception inner, String persistedState) at System.Web.UI.HiddenFieldPageStatePersister.Load() at System.Web.UI.Page.LoadPageStateFromPersistenceMedium() at System.Web.UI.Page.LoadAllState() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest() at System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) at System.Web.UI.Page.ProcessRequest(HttpContext context) at ASP.listing_aspx.ProcessRequest(HttpContext context) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Answer 1

The problem with Viewstate errors is that they don't tell you much and are hard to troubleshoot. Is this something that just started? Does this ony happen in the live site or is it something that can be reproduced?

Here's a place to start http://support.microsoft.com/kb/555353

and another http://weblogs.asp.net/owscott/archive/2004/11/02/What-causes-ViewState-Errors.aspx

Answer 2

Hi,

A little more information in the question would be handy. Does this happen every time, for every user, when doing a particular thing? Or - is it just a random message in your error log which happens very rarely?

If it's the latter, then it looks like someone is either trying to play around with the ViewState before it gets posted back to you (possibly in a failed attempt to do something nasty to your server), or for some reason the ViewState is getting corrupted for one of your visitors. Could be anything from a strange browser problem to dodgy software on the client PC?!

Answer 3

The error message includes:

Invalid length for a Base-64 char array.

Can you check the length of the ViewState that your page is generating? Some browsers are known to trim the ViewState, if it gets too long...