Problem with pie chart

[Cleanwatts]

I've been using ChartView for some time to create charts from a Windows service without problems. The chart control (RadCartesianChart or RadPieChart) is created and initialized in code, and then is rendered to a bitmap.

Ever since I updated the libraries to the latest version, when I try to create a pie chart, the result is always a blank image. The other chart types continue to work as expected.

The code I'm using is the following:

 

private bool CreatePieChartThread(MemoryStream stream, int width, int height)
{
    RadPieChart chart = new RadPieChart
                   {
                       Palette = BuildColorPalette(m_chartColors),
                       SmartLabelsStrategy = new PieChartSmartLabelsStrategy
                                         {
                                             DisplayMode = PieChartLabelsDisplayMode.SpiderAlignedOutwards
                                         }
                   };

    var labelBoxFactory = new FrameworkElementFactory(typeof(TextBlock));
    labelBoxFactory.SetValue(FrameworkElement.HorizontalAlignmentProperty, HorizontalAlignment.Center);
    labelBoxFactory.SetBinding(TextBlock.TextProperty, new Binding("Label"));

    var valueBoxFactory = new FrameworkElementFactory(typeof(TextBlock));
    valueBoxFactory.SetValue(FrameworkElement.HorizontalAlignmentProperty, HorizontalAlignment.Center);
    valueBoxFactory.SetBinding(TextBlock.TextProperty, new Binding("Value"));

    var panelFactory = new FrameworkElementFactory(typeof(StackPanel));
    panelFactory.SetValue(StackPanel.OrientationProperty, Orientation.Vertical);
    panelFactory.AppendChild(labelBoxFactory);

    if (m_showValuesOnPie)
        panelFactory.AppendChild(valueBoxFactory);

    PieSeries series = new PieSeries
                  {
                      ShowLabels = true,
                      RadiusFactor = 0.75,
                      AngleRange = new AngleRange(-90, 360),
                      LabelConnectorsSettings = new ChartSeriesLabelConnectorsSettings()
                  };
    series.LabelDefinitions.Add(new ChartSeriesLabelDefinition
                           {
                               Margin = new Thickness(-8, 0, 0, 0),
                               Template = new DataTemplate { VisualTree = panelFactory }
                           });

    // valores ordenados por nome e sem zeros
    foreach (var value in m_data.Where(d => d.AlarmOccurrences > 0).OrderBy(d => d.Name))
    {
        series.DataPoints.Add(new PieDataPoint
                         {
                             Label = value.Name,
                             Value = value.AlarmOccurrences,
                             OffsetFromCenter = 0.05,
                         });
    }

    chart.Series.Add(series);

    PrepareElementForExport(chart, width, height);
    ExportExtensions.ExportToImage(chart, stream, new PngBitmapEncoder());

    return true;
}

protected void PrepareElementForExport(FrameworkElement element, int width, int height)
{
    if (!element.IsInitialized)
    {
        element.BeginInit();
        element.EndInit();
    }

    element.Measure(Size.Empty);
    element.Measure(new Size(width, height));

    element.Dispatcher.Invoke(() => { });

    element.Arrange(new Rect(0, 0, width, height));
    element.UpdateLayout();
}

[Cleanwatts]

I forgot about some charts I have created using RadPolarChart. I have tried to create some and these also appear blank.

[Cleanwatts]

I also have some charts created using RadPolarChart. These are also rendering a blank image.

[Martin Ivanov]

Hello,

I tested your code and the pie chart is exported to an image properly. Can you take a look at the attached project and let me know if I am missing something? Additionally, you can double check the referenced assemblies are NoXaml. In this case you will need to merge some styles as explained in the Setting a Theme help article.

Regards,
Martin Ivanov
Progress Telerik

[Cleanwatts]

Hello,

I was using the NoXaml libraries by mistake. I have switched to the other libraries and the problem was gone.

Thanks for the advice.