Exception when trying to load assembly with custom functions

[Håvard]

I have a very small library which consists of a single class;

 public static class DateTimeFunctions
    {
        [Function(Category = "​xxx", Namespace = "​xxx", Description = "Get the start of current month")]
        public static DateTime StartOfMonth()
        {
            var now = DateTime.Now;
            return new DateTime(now.Year, now.Month, 1);
        }

        [Function(Category = "​xxx", Namespace = "xxx", Description = "Get the end of current month")]
        public static DateTime EndOfMonth()
        {
            return StartOfMonth().AddMonths(1) - TimeSpan.FromSeconds(1);
        }
    }

 In my app.config file I have the following:

 

configuration>
  <configSections>
    <section name="Telerik.Reporting"
             type="Telerik.Reporting.Configuration.ReportingConfigurationSection, Telerik.Reporting"
             allowLocation="true"
             allowDefinition="Everywhere"/>
  </configSections>

  <Telerik.Reporting>
    <AssemblyReferences>
      <add name="Name.Of.My.Assembly" version="1.0.0.0" culture="neutral" publicKeyToken="null" />
    </AssemblyReferences>
  </Telerik.Reporting>​

I have verified that both Telerik.Reporting.dll and my own assembly is located in the root folder of my applicattion.

 When I try to load the WPF ReportViewer component I get the following exception

Object reference not set to an instance of an object.

at Telerik.ReportViewer.Wpf.ReportViewerModel.ApplyValuesOnReportSource(ReportSource rs)
   at Telerik.ReportViewer.Wpf.ReportViewerModel.CreateReportSourceSnapshot(ReportSource source)
   at Telerik.ReportViewer.Wpf.ReportViewerModel.CreateHistoryRecord(ReportSource source, Boolean isTemporary)
   at Telerik.ReportViewer.Wpf.ReportViewerModel.LogHistory(ReportSource source, LogHistoryRecord logHistory, Boolean logTemporaryHistoryRecord)
   at Telerik.ReportViewer.Wpf.ReportViewerModel.RefreshReportCore(Boolean reloadParameters, LogHistoryRecord logHistory)
   at Telerik.ReportViewer.Wpf.ReportViewerModel.RefreshReport()
   at Telerik.ReportViewer.Wpf.ReportViewer.Refresh()
   at Telerik.ReportViewer.Wpf.ReportViewer.OnLoaded(Object sender, RoutedEventArgs e)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at MS.Internal.FrameworkObject.OnLoaded(RoutedEventArgs args)
   at System.Windows.BroadcastEventHelper.BroadcastEvent(DependencyObject root, RoutedEvent routedEvent)
   at System.Windows.BroadcastEventHelper.BroadcastLoadedEvent(Object root)
   at System.Windows.Media.MediaContext.FireLoadedPendingCallbacks()
   at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
   at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
   at System.Windows.Interop.HwndTarget.OnResize()
   at System.Windows.Interop.HwndTarget.HandleMessage(WindowMessage msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

[Håvard]

I resolved the issue. I'll post the solution in case someone else makes the same mistake as me: 

 The problem was that I included the class name in my report binding [=My.Assembly.DateTimeFunctions.StartOfMonth()] but the class name should actually be omitted, I suppose it might be because I declared the namespace like this (not included in the original post):

 [Function(Category = "​xxx", Namespace = "​My.Assembly", Description = "Get the start of current month")]

[Stef]

Hi Håvard,

I am glad to hear the issue is resolved.

For anyone concerned, please check the Previewing a report definition that uses an external assembly KB article, The article elaborates on how to deploy reports with custom functions.

Regards,
Stef
Telerik