NullReferenceException on deferred load of series

[Alex]

This sample raises NullReferenceException in tha AxisX.CalculateItemRange method

View:
<Window.Resources>

        <DataTemplate x:Key="measTemplate">

            <telerik:RadChart ItemsSource="{Binding ChartData, Mode=OneWay}" >

                <telerik:RadChart.DefaultView>

                    <telerik:ChartDefaultView>

                        <telerik:ChartDefaultView.ChartLegend>

                            <telerik:ChartLegend UseAutoGeneratedItems="True" Header=" " x:Name="chartLegend">

                            </telerik:ChartLegend>

                        </telerik:ChartDefaultView.ChartLegend>

                        <telerik:ChartDefaultView.ChartArea>

                            <telerik:ChartArea LegendName="chartLegend" EnableAnimations="True">

                                <telerik:ChartArea.AxisX>

                                    <telerik:AxisX />

                                </telerik:ChartArea.AxisX>

                                <telerik:ChartArea.AxisY>

                                    <telerik:AxisY DefaultLabelFormat="F2"/>

                                </telerik:ChartArea.AxisY>

                                <telerik:ChartArea.AdditionalYAxes>

                                    <telerik:AxisY AxisName="Secondary" DefaultLabelFormat="F2"/>

                                </telerik:ChartArea.AdditionalYAxes>

                            </telerik:ChartArea>

                        </telerik:ChartDefaultView.ChartArea>

                    </telerik:ChartDefaultView>

                </telerik:RadChart.DefaultView>

                <telerik:RadChart.SeriesMappings>

                    <telerik:SeriesMapping LegendLabel="R">

                        <telerik:SeriesMapping.SeriesDefinition>

                            <telerik:LineSeriesDefinition ShowItemLabels="False" AxisName="Secondary"/>

                        </telerik:SeriesMapping.SeriesDefinition>

                        <telerik:ItemMapping FieldName="ValueY" DataPointMember="YValue"/>

                        <telerik:ItemMapping FieldName="ValueX" DataPointMember="XValue"/>

                    </telerik:SeriesMapping>

                    <telerik:SeriesMapping LegendLabel="C">

                        <telerik:SeriesMapping.SeriesDefinition>

                            <telerik:LineSeriesDefinition ShowItemLabels="False"/>

                        </telerik:SeriesMapping.SeriesDefinition>

                        <telerik:ItemMapping FieldName="ValueY1" DataPointMember="YValue"/>

                        <telerik:ItemMapping FieldName="ValueX" DataPointMember="XValue"/>

                    </telerik:SeriesMapping>

                </telerik:RadChart.SeriesMappings>

            </telerik:RadChart>

        </DataTemplate>

    </Window.Resources>

    <DockPanel>

        <ItemsControl ItemsSource="{Binding Context.Charts}" ItemTemplate="{StaticResource measTemplate}">

            <ItemsControl.ItemsPanel>

                <ItemsPanelTemplate>

                    <UniformGrid Columns="1" />

                </ItemsPanelTemplate>

            </ItemsControl.ItemsPanel>

        </ItemsControl>

    </DockPanel>

View CodeBehind 
public partial class MainWindow : Window

    {
        public MainWindow()
        {
            InitializeComponent();
            this.Context = new Context();
            this.DataContext = this;
        }


        public Context Context { get; set; }
    }


    public class Context
    {
        public Context()
        {
            this.Charts = new ObservableCollection<ChartDataHolder>();
            for (int i = 0; i < 2; i++)
            {
                this.Charts.Add(new ChartDataHolder());
            }
        }


        public ObservableCollection<ChartDataHolder> Charts { get; private set; }
    }

ViewModel:

public class ChartDataHolder

    {

        private readonly BackgroundWorker worker = new BackgroundWorker();

 

        public ChartDataHolder()

        {
this.ChartData = new ObservableCollection<ChartDataItem>();


            worker.DoWork += this.worker_DoWork;

            this.worker.RunWorkerAsync();

 

        }

 

        void worker_DoWork(object sender, DoWorkEventArgs e)

        {

            Thread.Sleep(TimeSpan.FromSeconds(1)); //!! Without it it works fine

            while (true)

            {

                for (int i = 0; i < 2; i++)

                {

                    Application.Current.Dispatcher.BeginInvoke(new Action(this.ProcessResult), null);

                }

                Thread.Sleep(TimeSpan.FromSeconds(5));

            }

        }

 

        private void ProcessResult()

        {

            this.ChartData.Clear();

            for (int i = 0; i < 20; i++)

            {

                this.ChartData.Add(new ChartDataItem() { ValueX = DateTime.Now.Second + i, ValueY = DateTime.Now.Second + i });

            }

        }

 

        public ObservableCollection<ChartDataItem> ChartData { get; private set; }

    }

[Ves]

Hi Alex,

You can find attached a small example, based on your code. It works fine at my end. Please, give it a try and let us know if it works correctly for you. Make sure you use the latest version -- currently Q1 2011 SP1.

Kind regards,
Ves
the Telerik team

[Alex]

Hi.
Thanks for the reply, but I have this problem in your sample too.
WPF 4.0 (4.0.30319)
Telerik.Windows.Controls.Charting.dll 2011.1.516.40

p.s. I temporary solve it using converter and usercontrol to manualy create new instance of the chart for every data template item. Without it I get this exception or all the charts have the same axis intervals according the last data items.

[Ves]

Hi Alex,

Thank you for the additional details. We were able to reproduce the problem locally. It is now logged and you can track it in our Public Issue Tracking System -- link. Please, use the workaround you have found for the time being.

I have updated your Telerik points for bringing this to our attention.

Kind regards,
Ves
the Telerik team

[Alex]

Hi. 
I found a new problem, now with the Y axis.
This code generates two charts with the same Y axises, but the Y axis at the first chart should have different values 

View:

 <Window.Resources>
            <DataTemplate x:Key="measTemplate">
                <telerik:RadChart ItemsSource="{Binding ChartData, Mode=OneWay}" >
                    <telerik:RadChart.DefaultView>
                        <telerik:ChartDefaultView>
                            <telerik:ChartDefaultView.ChartLegend>
                                <telerik:ChartLegend UseAutoGeneratedItems="True" Header=" " x:Name="chartLegend">
                                </telerik:ChartLegend>
                            </telerik:ChartDefaultView.ChartLegend>
                            <telerik:ChartDefaultView.ChartArea>
                                <telerik:ChartArea LegendName="chartLegend" EnableAnimations="True">
                                    <telerik:ChartArea.AxisX>
                                        <telerik:AxisX />
                                    </telerik:ChartArea.AxisX>
                                    <telerik:ChartArea.AxisY>
                                        <telerik:AxisY DefaultLabelFormat="F2"/>
                                    </telerik:ChartArea.AxisY>
                                </telerik:ChartArea>
                            </telerik:ChartDefaultView.ChartArea>
                        </telerik:ChartDefaultView>
                    </telerik:RadChart.DefaultView>
                    <telerik:RadChart.SeriesMappings>
                        <telerik:SeriesMapping LegendLabel="C">
                            <telerik:SeriesMapping.SeriesDefinition>
                                <telerik:LineSeriesDefinition ShowItemLabels="False"/>
                            </telerik:SeriesMapping.SeriesDefinition>
                            <telerik:ItemMapping FieldName="ValueY" DataPointMember="YValue"/>
                            <telerik:ItemMapping FieldName="ValueX" DataPointMember="XValue"/>
                        </telerik:SeriesMapping>
                    </telerik:RadChart.SeriesMappings>
                </telerik:RadChart>
            </DataTemplate>
        </Window.Resources>
        <DockPanel>
            <ItemsControl ItemsSource="{Binding Context.Charts}" ItemTemplate="{StaticResource measTemplate}">
                <ItemsControl.ItemsPanel>
                    <ItemsPanelTemplate>
                        <UniformGrid Columns="1" />
                    </ItemsPanelTemplate>
                </ItemsControl.ItemsPanel>
            </ItemsControl>
        </DockPanel>

Codebehind

    public partial class XAxisTest : Window
    {
        public XAxisTest()
        {
            InitializeComponent();
            InitializeComponent();
            this.Context = new Context();
            this.DataContext = this;
        }

        public Context Context { get; set; }
    }

    public class Context
    {
        public Context()
        {
            this.Charts = new ObservableCollection<ChartDataHolder>();
            this.Charts.Add(new ChartDataHolder(1));
            this.Charts.Add(new ChartDataHolder(100));
        }


        public ObservableCollection<ChartDataHolder> Charts { get; private set; }
    }

    public class ChartDataHolder
    {
        public ChartDataHolder(double delta)
        {
            this.ChartData = new ObservableCollection<ChartDataItem>();
            for (int i = 0; i < 20; i++)
            {
                this.ChartData.Add(new ChartDataItem() { ValueX = DateTime.Now.Second + i, ValueY = DateTime.Now.Second * delta + i });
            }
        }

        public ObservableCollection<ChartDataItem> ChartData { get; private set; }
    }

    public class ChartDataItem
    {
        public int ValueX { get; set; }
        public double ValueY { get; set; }
    }

[Ves]

Hello Alex,

Indeed, the problem exists in WPF 3.5 only. You can find it discussed in details along with a possible workaround in this forum thread.

Regards,
Ves
the Telerik team

[Alex]

Hi, thanks for the link, but as I already wrote, I use WPF 4.0 (4.0.30319) so this problem exists not in WPF 3.5 only.

[Ves]

Hi Alex,

I am sorry for omitting this. I can confirm this is a bug in the control. You can track it here.  I have updated your Telerik points again.

Best regards,
Ves
the Telerik team