Inconsistent error using multiple datasources

[HDC]

I have a Chart using 3 domain datasources for loading data (displaying only one for demonstration)

<telerik:RadDomainDataSource AutoLoad="True" Height="0" Width="0"
                                    x:Name="invoiceStatisticsDomainDataSource1"
                                    QueryName="GetInvoiceStatisticsQuery"
                                    >
  <telerik:RadDomainDataSource.DomainContext>
    <my1:ExqiOfficeDomainContext />
  </telerik:RadDomainDataSource.DomainContext>
  <telerik:RadDomainDataSource.QueryParameters>
    <telerik:QueryParameter ParameterName="serviceId" Value="1"/>
    <telerik:QueryParameter ParameterName="months" Value="4"/>
  </telerik:RadDomainDataSource.QueryParameters>
</telerik:RadDomainDataSource>

I have made a chart based on the datasources:

<telerik:RadChart Grid.Row="1" Grid.Column="1">
  <telerik:RadChart.SeriesMappings>
    <telerik:SeriesMapping LegendLabel="title" ItemsSource="{Binding DataView, ElementName=invoiceStatisticsDomainDataSource1}">
      <telerik:SeriesMapping.SeriesDefinition>
        <telerik:StackedBarSeriesDefinition StackGroupName="Description" ></telerik:StackedBarSeriesDefinition>
      </telerik:SeriesMapping.SeriesDefinition>
      <telerik:SeriesMapping.ItemMappings>
        <telerik:ItemMapping DataPointMember="XValue" FieldName="Month" ></telerik:ItemMapping>
        <telerik:ItemMapping DataPointMember="YValue" FieldName="TotalAmount" ></telerik:ItemMapping>
      </telerik:SeriesMapping.ItemMappings>
    </telerik:SeriesMapping>
    <telerik:SeriesMapping LegendLabel="Test" ItemsSource="{Binding DataView, ElementName=invoiceStatisticsDomainDataSource2}">
      <telerik:SeriesMapping.SeriesDefinition>
        <telerik:StackedBarSeriesDefinition StackGroupName="Description"></telerik:StackedBarSeriesDefinition>
      </telerik:SeriesMapping.SeriesDefinition>
      <telerik:SeriesMapping.ItemMappings>
        <telerik:ItemMapping DataPointMember="XValue" FieldName="Month" ></telerik:ItemMapping>
        <telerik:ItemMapping DataPointMember="YValue" FieldName="TotalAmount"></telerik:ItemMapping>
      </telerik:SeriesMapping.ItemMappings>
    </telerik:SeriesMapping>
    <telerik:SeriesMapping LegendLabel="Free Invoices" ItemsSource="{Binding DataView, ElementName=invoiceStatisticsDomainDataSource3}">
      <telerik:SeriesMapping.SeriesDefinition>
        <telerik:StackedBarSeriesDefinition StackGroupName="Description"></telerik:StackedBarSeriesDefinition>
      </telerik:SeriesMapping.SeriesDefinition>
      <telerik:SeriesMapping.ItemMappings>
        <telerik:ItemMapping DataPointMember="XValue" FieldName="Month" ></telerik:ItemMapping>
        <telerik:ItemMapping DataPointMember="YValue" FieldName="TotalAmount"></telerik:ItemMapping>
      </telerik:SeriesMapping.ItemMappings>
    </telerik:SeriesMapping>

  </telerik:RadChart.SeriesMappings>
  <telerik:RadChart.DefaultView>
    <telerik:ChartDefaultView>
      <telerik:ChartDefaultView.ChartTitle>
        <telerik:ChartTitle Content="Invoiced Amount/Month"></telerik:ChartTitle>
      </telerik:ChartDefaultView.ChartTitle>
      <telerik:ChartDefaultView.ChartArea>
        <telerik:ChartArea LegendName="CustomLegend">
          <telerik:ChartArea.AxisX>
            <telerik:AxisX Title="Period" />
          </telerik:ChartArea.AxisX>
          <telerik:ChartArea.AxisY>
            <telerik:AxisY MajorGridLinesVisibility="Visible"
                                           MinorTicksVisibility="Visible"
                                           Title="Total Invoiced (EUR)"
                                           >
            </telerik:AxisY>
          </telerik:ChartArea.AxisY>
        </telerik:ChartArea>
      </telerik:ChartDefaultView.ChartArea>
      <telerik:ChartDefaultView.ChartLegend>
        <telerik:ChartLegend x:Name="CustomLegend" UseAutoGeneratedItems="True" BorderThickness="1,0,0,0" />
      </telerik:ChartDefaultView.ChartLegend>
    </telerik:ChartDefaultView>
  </telerik:RadChart.DefaultView>
</telerik:RadChart>

Sometimes i can run this chart without any problem, but from time to time (more often then not) i get following error (code breaks in XAML page on the UserControl tag)

System.Reflection.TargetInvocationException was unhandled by user code
  Message=[Arg_TargetInvocationException]
Arguments:
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=5.0.60401.00&File=mscorlib.dll&Key=Arg_TargetInvocationException
  StackTrace:
       at System.RuntimeMethodHandle._InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
       at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
       at System.Delegate.DynamicInvokeImpl(Object[] args)
       at System.Delegate.DynamicInvoke(Object[] args)
       at DashboardViewxaml.BindingOperation_66_74(Object BindingState, Action )
  InnerException: System.NullReferenceException
       Message=[Arg_NullReferenceException]
Arguments:
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=5.0.60401.00&File=mscorlib.dll&Key=Arg_NullReferenceException
       StackTrace:
            at Telerik.Windows.Controls.Charting.DataBindingHelper.ProcessMapping(SeriesMapping seriesMapping, QueryableCollectionView dataEngine, Int32 samplingThreshold, ZoomScrollSettings zoomScrollSettings, ISeriesDefinition defaultSeriesDefinition, AxisRangeState axisXRangeState)
            at Telerik.Windows.Controls.Charting.DataBindingHelper.ProcessMappings(SeriesMappingCollection seriesMappings, QueryableCollectionView dataEngine, Int32 samplingThreshold, ZoomScrollSettings zoomScrollSettings, ISeriesDefinition defaultSeriesDefinition, AxisRangeState axisXRangeState)
            at Telerik.Windows.Controls.Charting.DataBindingHelper.GenerateDataSeries(Object originalData, SeriesMappingCollection seriesMappings, ISeriesDefinition defaultSeriesDefinition, ChartFilterDescriptorCollection globalFilterDescriptors, ChartSortDescriptorCollection globalSortDescriptors, SamplingSettings samplingSettings, ZoomScrollSettings zoomScrollSettings, AxisRangeState axisXRangeState)
            at Telerik.Windows.Controls.RadChart.GenerateDataSeries(Object originalData, SeriesMappingCollection seriesMappings, ChartArea chartArea)
            at Telerik.Windows.Controls.RadChart.GenerateDataSeries(Object originalData)
            at Telerik.Windows.Controls.RadChart.Rebind(Object originalData)
            at Telerik.Windows.Controls.RadChart.Rebind()
            at Telerik.Windows.Controls.Charting.SeriesMapping.RebindChart()
            at Telerik.Windows.Controls.Charting.SeriesMapping.ManageChangeNotifications(Object originalData, Object oldData)
            at Telerik.Windows.Controls.Charting.SeriesMapping.ItemsSourcePropertyChanged(DependencyObject target, DependencyPropertyChangedEventArgs args)
            at Telerik.Windows.PropertyMetadata.<>c__DisplayClass1.<Create>b__0(DependencyObject d, DependencyPropertyChangedEventArgs e)
            at System.Windows.DependencyObject.RaisePropertyChangeNotifications(DependencyProperty dp, Object oldValue, Object newValue)
            at System.Windows.DependencyObject.UpdateEffectiveValue(DependencyProperty property, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, ValueOperation operation)
            at System.Windows.DependencyObject.RefreshExpression(DependencyProperty dp)
            at System.Windows.Data.BindingExpression.SendDataToTarget()
            at System.Windows.Data.BindingExpression.SourceAcquired()
            at System.Windows.Data.BindingExpression.PerformTargetLoaded()
            at System.Windows.Data.Debugging.BindingBreakPoint.<>c__DisplayClass1.<BreakOnSingleType>b__0()
       InnerException:

I can't make heads not tails about this

[Yavor]

Hi peter,

We have tested your scenario in our environment using 3 DomainDataSources pointing to the same RIA service. The test system makes a new call to the RIA service for data every 15 seconds, but unfortunately we couldn't reproduce the mentioned error. I have attached the test project so that you can test it in your environment.

If the problem persists please open a support ticket and attach your project so that we can investigate it and advice you how to proceed.

Kind regards,
Yavor Ivanov
the Telerik team

[HDC]

Thanks a lot for taking the time to send a sample. I appreciate it.

I can't run the sample because i get an incompatibility exception with the version of the database but when i launch the code, i don't immediately get an error. The only difference i see is the fact that your code uses a timer to load the data. Is this is a requirement?

Meanwhile, i have decided to use a different approach to the same problem, using a single datasource and filterdescriptions i was able to solve my problem just today.

For those interested here is my code:

<telerik:RadChart x:Name="InvoiceChart" Grid.Row="1" Grid.Column="0" ItemsSource="{Binding DataView, ElementName=invoiceStatisticsDomainDataSource1}">
  <telerik:RadChart.SeriesMappings>
    <telerik:SeriesMapping LegendLabel="ExqiPresenter">
      <telerik:SeriesMapping.FilterDescriptors>
        <telerik:FilterDescriptor Operator="IsEqualTo" Member="ServiceId" Value="1">
        </telerik:FilterDescriptor>
      </telerik:SeriesMapping.FilterDescriptors>
      <telerik:SeriesMapping.SeriesDefinition>
        <telerik:StackedBarSeriesDefinition StackGroupName="Description" ></telerik:StackedBarSeriesDefinition>
      </telerik:SeriesMapping.SeriesDefinition>
      <telerik:SeriesMapping.ItemMappings>
        <telerik:ItemMapping DataPointMember="XValue" FieldName="Month" ></telerik:ItemMapping>
        <telerik:ItemMapping DataPointMember="YValue" FieldName="TotalAmount" ></telerik:ItemMapping>
      </telerik:SeriesMapping.ItemMappings>
    </telerik:SeriesMapping>
    <telerik:SeriesMapping LegendLabel="Test">
      <telerik:SeriesMapping.FilterDescriptors>
        <telerik:FilterDescriptor Operator="IsEqualTo" Member="ServiceId" Value="2">
        </telerik:FilterDescriptor>
      </telerik:SeriesMapping.FilterDescriptors>
      <telerik:SeriesMapping.SeriesDefinition>
        <telerik:StackedBarSeriesDefinition StackGroupName="Description" ></telerik:StackedBarSeriesDefinition>
      </telerik:SeriesMapping.SeriesDefinition>
      <telerik:SeriesMapping.ItemMappings>
        <telerik:ItemMapping DataPointMember="XValue" FieldName="Month" ></telerik:ItemMapping>
        <telerik:ItemMapping DataPointMember="YValue" FieldName="TotalAmount" ></telerik:ItemMapping>
      </telerik:SeriesMapping.ItemMappings>
    </telerik:SeriesMapping>

This is in my oppinion a much better solution because it only executes one call to domainservices, the only challenge is that i have to merge my data coming from the Entity Framework. To this end i created a complex type on my Entity Model. I can then run multiple queries and merge the data together:

List<InvoiceStatistics> discountstatistics = discounts.ToList().Select(r => new InvoiceStatistics() { Month = r.Month, TotalAmount = r.TotalAmount }).ToList<InvoiceStatistics>();
      foreach (InvoiceStatistics discountstatistic in discountstatistics)
      {
        statistics.Add(new InvoiceStatistics() { ServiceId=-1, Description="Discount", Month = discountstatistic.Month, TotalAmount = discountstatistic.TotalAmount });
      }

It may not be solution if you have heavy statistics with many thousands of datapoints, but in my case i have 3 statistics that have the same data layout anyway and only one query (discounts) which is different. Because i don't have to execute 4 queries (but only 2) the performance of this solution is even better!

This suits my needs for now.

Thanks again for the sample!