Bind Pie Chart to Linq

[Andrew]

From what i understand this should be possible and very easy, but i must be missing something...

Dim SumData = From S In _DataStockInfoList Group S By Key = S.CategoryDescription Into Group Select Supplier = Key, StockValue = Group.Sum(Function(S) S.TotalCost)

Me.StockValueSeries.ItemsSource = SumData *** Gives me a runtime error Null object !!

And my xaml

                  <telerik:RadPieChart x:Name="PieChartStockValue" Palette="Metro" >
                        <telerik:PieSeries x:Name="StockValueSeries" ShowLabels="True" RadiusFactor="0.7" ValueBinding="StockValue" ItemsSource="{Binding}" >
                            <telerik:PieSeries.LabelDefinitions>
                                <telerik:ChartSeriesLabelDefinition Margin="-30,0,0,0"/>
                            </telerik:PieSeries.LabelDefinitions>
                            <telerik:PieSeries.AngleRange>
                                <telerik:AngleRange  SweepAngle="360" />
                            </telerik:PieSeries.AngleRange>
                        </telerik:PieSeries>
                    </telerik:RadPieChart>

[Petar Kirov]

Hi Andy,

I believe that the null-reference error you are getting is caused not by the binding of the ItemSource (or the LINQ), but the the fact that StockValueSeries is null at runtime.

The reason for the error is that you can't refer to a series object by its x:Name. Here you can find more information on the matter.

You can fix that by either:

• Setting SumData to the DataContext of the UserControl or the RadPieChart
• Referencing the series by its index in the chart.Series collection. For example: 

  Me.PieChartStockValue.Series(0).ItemsSource = SumData

I hope this helps.

Regards,
Petar Kirov
the Telerik team

[Andrew]

Still Not there

Code behind is

Dim SumData = From S In _DataStockInfoList Group S By Key = S.CategoryDescription Into Group Select Supplier = Key, StockValue = Group.Sum(Function(S) S.TotalCost)

Me.PieChartStockValue.Series(0).ItemsSource = SumData

Xaml is

<telerik:RadPieChart x:Name="PieChartStockValue" Palette="Metro" >
                        <telerik:PieSeries  ShowLabels="True" RadiusFactor="0.7" ValueBinding="StockValue" ItemsSource="{Binding}">
                            <telerik:PieSeries.LabelDefinitions>
                                <telerik:ChartSeriesLabelDefinition Margin="-30,0,0,0"/>
                            </telerik:PieSeries.LabelDefinitions>
                            <telerik:PieSeries.AngleRange>
                                <telerik:AngleRange  SweepAngle="360" />
                            </telerik:PieSeries.AngleRange>
                        </telerik:PieSeries>
                    </telerik:RadPieChart>

And I now get the following error at runtime

Attempt by security transparent method 'DynamicClass.Telerik_DynamicGetter_StockValue(System.Object)' to access security critical type 'VB$AnonymousType_6`2<System.String,System.Decimal>' failed.

[Petar Kirov]

Hi Andy,

The problem is related to anonymous classes. Please, create a small class containing the properties you need as a result of the LINQ expression and pass the resulting collection to chart series ItemsSource. For example: 

Public Class DataItem
    Public Property Supplier As String
    Public Property StockValue As Double
End Class


'Old:
Dim SumData = From S In _DataStockInfoList Group S By Key = S.CategoryDescription Into Group
  Select Supplier = Key, StockValue = Group.Sum(Function(S) S.TotalCost)

'New:
Dim sumData = From S In _DataStockInfoList _
         Group S By Key = S.CategoryDescription Into Group _
         Select New DataItem With { _
          .Supplier = Key, _
          .StockValue = Group.Sum(Function(s) s.TotalCost)}

Me.PieChartStockValue.Series(0).ItemsSource = sumData

Regards,
Petar Kirov
the Telerik team

[Andrew]

That work around works

Thank you