ArgumentException while binding

[Petr]

Hey,

I am evaluating the telerik chart component (trial version) for its suitability for our software project, and can not bring the RadCartesianChart to work.  

I am trying to put a new view atop of an existing viewmodel, and bind the chart data to a property of type ObeservableCollection<KeyValuePair<int, double>>. When the collection is empty its ok, but when trying to populate it, I get
ArgumentException: Dynamic getter is not supported for value types. 

Any idea why this happens and what the solution is? 

My code: View:

<telerik:RadCartesianChart Grid.Row="1">
            <telerik:RadCartesianChart.HorizontalAxis>
                <telerik:LinearAxis/>
            </telerik:RadCartesianChart.HorizontalAxis>

            <telerik:RadCartesianChart.VerticalAxis>
                <telerik:LinearAxis/>
            </telerik:RadCartesianChart.VerticalAxis>

            <telerik:RadCartesianChart.Series>
                <telerik:ScatterLineSeries XValueBinding="Key"
                       YValueBinding="Value"
                       ItemsSource="{Binding Path=DataSeries}">

                </telerik:ScatterLineSeries>
            </telerik:RadCartesianChart.Series>

        </telerik:RadCartesianChart>

And the view model:

// populated in Constructor
       private ObservableCollection<KeyValuePair<int, double>> mTempRandomData = new ObservableCollection<KeyValuePair<int, double>>();

       private ObservableCollection < KeyValuePair <int, double> > mDataSeries = new ObservableCollection < KeyValuePair < int, double > > ();

        public ObservableCollection<KeyValuePair<int, double>> DataSeries
        {
            get { return mDataSeries; }
            set { mDataSeries = value; RaisePropertyChanged ( ()=>DataSeries );
            }
        }

        private void DoResetData ( )
        {
            DataSeries = new ObservableCollection < KeyValuePair < int, double > > ();
        }
        private void DoAddRandomData()
        {
            DoResetData (  );
            DataSeries = mTempRandomData;

        }

[Petar Marchev]

Hello Petr,

When creating the XValueBinding (and the other bindings) in XAML, the parser creates a PropertyNameDataPointBinding and sets it to the XValueBinding (help topic here). This type of binding can only work with reference types and not with value types. Since the KeyValuePair is a struct - the chart cannot work with it, thus the exception is thrown.

You can use another type of DataPointBinding we have  - the GenericDataPointBinding. This is how you can use it:

var dpb = new GenericDataPointBinding<KeyValuePair<int, double>, int>();
dpb.ValueSelector = pair => pair.Key;

scatterSeries.XValueBinding = dpb;

Do try this and see how it goes. Let us know if you need further assistance.

Kind regards,
Petar Marchev
the Telerik team