We are using the Telerik Treeview control and intermittently we are getting and invalid viewstate error. Here are some of the details of the exception:

Message: Exception Type:        System.FormatException
Exception Message:     Invalid length for a Base-64 char array.
Exception Source:      mscorlib
Exception Target Site: FromBase64String

(Outer Exception)
Exception Type:        System.Web.UI.ViewStateException
Exception Message:     Invalid viewstate.


 __EVENTTARGET                 RadTreeView1
 __EVENTARGUMENT               {"commandName":"Collapse","index":"43:0:0:0:0"}

Any ideas why this error may be happening?

Thanks
Som

Hi Som,

Can you paste the code here or ideally open a support thread and attach a sample project so we can reproduce the problem locally.

You can also check this forum post.

Kind regards,
Veselin Vasilev
the Telerik team