Hi,

I'm writing tests for the usual reason.  I have a XamChart where I've added a drag feature for the user.  The user can select a data point and move it up and down.  The backing custom class is updated which cascades the update to a XamDataGrid.  Everything works fine, but I'm running into problems during testing.  Specifically, this line throws an exception:

 var hitArgs = xamChart.HitTest(e);

Here is the exception:

System.NullReferenceException was unhandled by user code
  Message=Object reference not set to an instance of an object.
  Source=InfragisticsWPF3.Chart.v10.2
  StackTrace:
       at Infragistics.Windows.Chart.XamChart.HitTest(MouseEventArgs e)
       at Intel.Wolf.UI.WPFMVApp.Helpers.XamChartHelper.MouseLeftButtonDownHandler(Object sender, MouseButtonEventArgs e) in C:\<...>\Helpers\XamChartHelper.cs:line 95
  InnerException:

If I run the code in the Immediate Window I get this:

? xamChart == null

false

? e == null

false

xamChart.HitTest(e)

'xamChart.HitTest(e)' threw an exception of type 'System.NullReferenceException'

base {System.SystemException}: {"Object reference not set to an instance of an object."}

What 'Object'?  Neither xamChart or e are null. 

Complete method:

private static void MouseLeftButtonDownHandler(object sender, MouseButtonEventArgs e)
    {
 
      var xamChart = sender as XamChart;
      if (xamChart == null || e == null)
        return;
 
      var hitArgs = xamChart.HitTest(e);
      selectedDataPoint = hitArgs.SelectedObject as DataPoint;
      if (selectedDataPoint != null)
      {
        xamChart.Cursor = Cursors.SizeNS;
        started = true;
      }
      e.Handled = true;
 
    }

Here is my test:

    [TestMethod]
    public void MouseLeftButtonDownHandlerTest()
    {
      var chart = new XamChart();
      chart.Width = 300; // ??? Create a size to be selected ???

      chart.Height = 300;
 
      XamChartHelper.SetChartDragging(chart, true);
 
      var e = new MouseButtonEventArgs(Mouse.PrimaryDevice, 0, MouseButton.Left);
      e.RoutedEvent = XamChart.MouseLeftButtonDownEvent;
      //chart.RaiseEvent(e);
 
      XamChartHelper_Accessor.MouseLeftButtonDownHandler(chart, e);
 
      // ToDo: Need more logic testing beyond "handled"
      Assert.IsTrue(e.Handled);
      
    }


 

VS 2010 Ultimate, Win7 x64, InfragisticsWPF3.Chart.v10.2

Can anyone point me in a direction?