[Solved] Defining a LabelDefinition.Template programmatically crashes browser?

[Colter]

Hello,

I have the following situation:

I am creating a dynamic number of bar/line series using the SeriesProvider class.

Unfortunately there does not seem to be a way to define a custom label definition within this class so I am waiting until the Loaded event is fired on my chart and trying to do it programmatically.

RadCartesianChart cartesianChart = chart as RadCartesianChart;

if (cartesianChart != null)
{
    // add label definitions since our chart series are created dynamically by Series Providers
    ChartSeriesLabelDefinition cartesianLabelDefintion = new ChartSeriesLabelDefinition();

    // Grab the data template from the resources
    if (Resources.Contains(CartesianLabelTemplateName))
    {
        DataTemplate labelTemplate = Resources[CartesianLabelTemplateName] as DataTemplate;
        if (labelTemplate != null)
        {
            cartesianLabelDefintion.Template = labelTemplate;
        }
    }

    // Default to a property binding if no template is found
    if(cartesianLabelDefintion.Template == null)
    {
        cartesianLabelDefintion.Binding = new PropertyNameDataPointBinding("FormattedValue");
    }

    cartesianChart.Series.ForEach(s =>
        {
            s.LabelDefinitions.Add(cartesianLabelDefintion);
        });

}

Which results in the following stack trace in Chrome when the chart tries to render.  For some reason I can't intercept this exception in Visual studio.

Uncaught Error: Unhandled Error in Silverlight Application Code: 4004 Category: ManagedRuntimeError Message: System.NullReferenceException: Object reference not set to an instance of an object. at Telerik.Windows.Controls.ChartView.ChartSeries.GetLabelVisual(ChartSeriesLabelUpdateContext context) at Telerik.Windows.Controls.ChartView.ChartSeries.ProcessLabelDefinition(ChartSeriesLabelUpdateContext context) at Telerik.Windows.Controls.ChartView.ChartSeries.ProcessDataPointLabels(ChartSeriesLabelUpdateContext context) at Telerik.Windows.Controls.ChartView.ChartSeries.UpdateLabels(ChartLayoutContext context) at Telerik.Windows.Controls.ChartView.ChartSeries.UpdateUICore(ChartLayoutContext context) at Telerik.Windows.Controls.ChartView.PointTemplateSeries.UpdateUICore(ChartLayoutContext context) at Telerik.Windows.Controls.ChartView.BarSeries.UpdateUICore(ChartLayoutContext context) at Telerik.Windows.Controls.ChartView.PresenterBase.UpdateUI(ChartLayoutContext context) at Telerik.Windows.Controls.ChartView.RadChartBase.UpdateUICore(ChartLayoutContext context) at Telerik.Windows.Controls.ChartView.PresenterBase.UpdateUI(ChartLayoutContext context) at Telerik.Windows.Controls.ChartView.RadChartBase.CallUpdateUI() at Telerik.Windows.Controls.ChartView.RadChartBase.ArrangeOverride(Size finalSize) at System.Windows.FrameworkElement.ArrangeOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)


Any thoughts?

Colter

[Peshito]

Hi Colter,

Wiring to the Loaded event is probably too early for the chart. What I could reccomend is setting the LabelDefinition in XAML. Please take a look at the following demo demonstrating the same approach using ChartSeriesProvider and LabelDefinition:
http://demos.telerik.com/silverlight/#ChartView/BrowsersChart

Hope this helps.

Regards,
Peshito
Telerik