Problem:

 I would like to know how I can catch errors that showup on my reportviewer web server control when for instance there is a parameter whose value was not set.

Solution:

You can you the ReportError method of the ReportViewer control. It has an 'e' argument of type ReportErrorEventArgs, which you can use to handle the error.

For example, I have a page where I use it like this:

Protected Sub ReportViewer1_ReportError(ByVal sender As Object, ByVal e As Microsoft.Reporting.WebForms.ReportErrorEventArgs) Handles ReportViewer1.ReportError 

        If TypeOf e.Exception Is AspNetSessionExpiredException Then 

        e.Handled = True 

        Session.Abandon() 

        FormsAuthentication.SignOut() 

        Response.Redirect(FormsAuthentication.LoginUrl, True) 

        Else 

        e.Handled = False 

        End If 

        End Sub

http://www.experts-exchange.com/Programming/Languages/.NET/ASP.NET/Q_23871497.html

http://www.codeprof.com/dev-archive/90/6-75-908431.shtm