How to generate chart image without showing it?

[Simon]

I would like to generate the charts without actually showing it (in a WPF application), and then save them to image.

However, when I run, I hit  the InvalidOperationException

[Simon]

Got some sample code. I hit 
                    InvalidOperationException: "The calling thread cannot access this object because a different thread owns it."

at this line:

                     chart.Save(path);

Please let me know what I can do to avoid this.

MainWindow.xaml:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Button Content="Save Graph" Height="22" HorizontalAlignment="Left" Margin="423,277,0,0" Name="button1" VerticalAlignment="Top" Width="80" Click="button1_Click" />
    </Grid>
</Window>


MainWindow.xaml.cs:

using System;
using System.Collections.Generic;
using System.Threading;
using System.Windows;
using System.Windows.Threading;
using Telerik.Windows.Controls;
using Telerik.Windows.Controls.Charting;

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            SaveChartProcessor _ruleProcessor = new SaveChartProcessor();
            _ruleProcessor.SaveImage();
        }
    }

    public class SaveChartProcessor
    {
        public void SaveImage()
        {
            var newThread = new Thread(processChartImageWorker);
            newThread.SetApartmentState(ApartmentState.STA);
            newThread.Start();
        }

        public void processChartImageWorker()
        {
            RadChart chart = GetChart();

            string path = "d:\\newpic.png";

            chart.Dispatcher.Invoke(
                    new Action(() =>
                    {
                        chart.Save(path);
                    }),
                    DispatcherPriority.Normal);
        }

        public RadChart GetChart()
        {
            var chart = new RadChart();
            chart.BeginInit();

            chart.Width = 640;
            chart.Height = 480;
            chart.DefaultView.ChartArea.EnableAnimations = false;

            SeriesMapping sm1 = new SeriesMapping();
            sm1.SeriesDefinition = new LineSeriesDefinition();
            sm1.LegendLabel = "Line Series 1";
            sm1.CollectionIndex = 0;
            ItemMapping im1 = new ItemMapping();
            im1.DataPointMember = DataPointMember.YValue;
            sm1.ItemMappings.Add(im1);
            SeriesMapping sm2 = new SeriesMapping();
            sm2.SeriesDefinition = new LineSeriesDefinition();
            sm2.LegendLabel = "Line Series 2";
            sm2.CollectionIndex = 1;
            ItemMapping im2 = new ItemMapping();
            im2.DataPointMember = DataPointMember.YValue;
            sm2.ItemMappings.Add(im2);

            // Force chart to measure itseft so it provides the actual width and height to export
            chart.Measure(new System.Windows.Size(chart.Width, chart.Height));
            chart.Arrange(new System.Windows.Rect(chart.DesiredSize));

            chart.SeriesMappings.Add(sm1);
            chart.SeriesMappings.Add(sm2);

            chart.EndInit();

            var itemsSource = new List<double>[] { new List<double> { 9, 2, 3, 4 }, new List<double> { 5, 7, 3, 4 } };
            chart.ItemsSource = itemsSource;
            return chart;
        }
    }
}

[Simon]

Why no one reply? Can some one help?

[Sia]

Hi Simon,

First of all, please excuse us for our late reply.
You can find a possible solution in the attached files. There a RadChart is added to the visual tree but in hidden container. Please let us know whether this is appropriate for your scenario.

Regards,
Sia
the Telerik team

[Simon]

No, I can't do this in my UI thread. In my case, I have to put the logic in a different class that doens't implement WPF window. I need to  spin out a separate thread that calls this class and this class has a function that create the RadChart then save it as image. can you try to modify my codes to see if you can get it working?

[Sia]

Hi Simon,

Please expect soon our answer in the other forum thread concerning the same issue.

Thank you,
Sia
the Telerik team