ExportToImage function throw null reference exception

[Thierry]

I try to use the function ExportToImage(Stream) from a RadChart object and it always throw an null reference exception whatever the chart I try. 

Here is a sample code I try to test the function :

List<int> data = new List<int>();
Random rand = new Random(123456);
for (int i = 0; i < 50; i++)
{
    data.Add(rand.Next(10, 100));
}

chartTest.DefaultSeriesDefinition = new LineSeriesDefinition() { ShowItemLabels = false, ShowPointMarks = false };
chartTest.DefaultView.ChartArea.AxisX.LabelStep = 25;
chartTest.DefaultView.ChartArea.EnableAnimations = false;
chartTest.ItemsSource = data;

Stream ms = new MemoryStream();
chartTest.ExportToImage(ms);
/*BitmapImage src = new BitmapImage();
src.BeginInit();
src.StreamSource = ms;
src.EndInit();

img1.Source = src;*/

Exception throw at this line :

chartTest.ExportToImage(ms);

Exception message :

{"Object reference not set to an instance of an object."}

Exception call stack :

   at Telerik.Windows.Media.Imaging.ExportHelper.get_TransformToDevice() in c:\Builds\WPF_Scrum\Release_WPF_2010_Q2_SP1\Sources\Development\Core\Controls\ExportExtensions\ExportHelper.cs:line 50
   at Telerik.Windows.Media.Imaging.ExportHelper.get_TransformToDeviceMatrix() in c:\Builds\WPF_Scrum\Release_WPF_2010_Q2_SP1\Sources\Development\Core\Controls\ExportExtensions\ExportHelper.cs:line 43
   at Telerik.Windows.Media.Imaging.ExportHelper.get_SystemDpiX() in c:\Builds\WPF_Scrum\Release_WPF_2010_Q2_SP1\Sources\Development\Core\Controls\ExportExtensions\ExportHelper.cs:line 16
   at Telerik.Windows.Media.Imaging.ExportHelper.GetElementImage(FrameworkElement element) in c:\Builds\WPF_Scrum\Release_WPF_2010_Q2_SP1\Sources\Development\Core\Controls\ExportExtensions\ExportHelper.cs:line 62
   at Telerik.Windows.Media.Imaging.ImageExporter.Export(FrameworkElement element, Stream stream, BitmapEncoder encoder) in c:\Builds\WPF_Scrum\Release_WPF_2010_Q2_SP1\Sources\Development\Core\Controls\ExportExtensions\ImageExporter.cs:line 12
   at Telerik.Windows.Media.Imaging.ExportExtensions.ExportToImage(FrameworkElement element, Stream stream, BitmapEncoder encoder) in c:\Builds\WPF_Scrum\Release_WPF_2010_Q2_SP1\Sources\Development\Core\Controls\ExportExtensions\ExportExtensions.cs:line 100
   at Telerik.Windows.Controls.RadChart.ExportToImage(Stream stream) in c:\Builds\WPF_Scrum\Release_WPF_2010_Q2_SP1\Sources\Development\Controls\Chart\Chart\RadChart.Exporting.cs:line 168
   at TestChart.MainWindow..ctor() in C:\Dev\TestChart\TestChart\MainWindow.xaml.cs:line 41

[Missing User]

Hi Thierry,

Try calling the ExportToImage(Stream) method when all components are loaded and initialized. For example on window loaded or button click event.

public MainWindow()
{
    InitializeComponent();

    List<int> data = new List<int>();
    Random rand = new Random(123456);
    for (int i = 0; i < 50; i++)
    {
        data.Add(rand.Next(10, 100));
    }

    chartTest.DefaultSeriesDefinition = new LineSeriesDefinition() { ShowItemLabels = false, ShowPointMarks = false };
    chartTest.DefaultView.ChartArea.AxisX.LabelStep = 25;
    chartTest.DefaultView.ChartArea.EnableAnimations = false;
    chartTest.ItemsSource = data;

}

private void Window_Loaded(object sender, RoutedEventArgs e)

{

    Stream memoryStream = new MemoryStream();

    chartTest.ExportToImage(memoryStream);


    BitmapImage bmpImage = new BitmapImage();

    bmpImage.BeginInit();

    bmpImage.StreamSource = memoryStream;

    bmpImage.EndInit();

    img1.Source = bmpImage;

}

Let me know whether the proposed solution helps.

Kind regards,

Polina

the Telerik team