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Chart Crash
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gerbrand
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gerbrand asked on 06 Nov 2009, 01:27 PM
Hi, I'm currently trying the charting component in my winform application. (version 2009.1.9.316)
Now I've got just a treeview and a chart component on my winform.
when I click on a treenode the chart view is loaded with the data, everything works fine.
now as long as my treeview isn't reloaded the chart loads the data, but when in my main form is triggered to reload the treeview and I click a treenode, my program crashes. with the following exception:

general exception:    at Telerik.Charting.Chart.GetException(RenderEngine renderEngine, Exception ex)
   at Telerik.Charting.Chart.GetImage(Int32 width, Int32 height)
   at Telerik.Charting.Chart.GetImage()
   at Telerik.WinControls.UI.RadChart.GetImage()
   at Telerik.WinControls.UI.RadChart.OnPaint(PaintEventArgs e)
  
in the innerexception I'm reading system.nullreferenceexception
   at Telerik.Charting.ChartSeriesItem.set_Parent(ChartSeries value)
   at Telerik.Charting.ChartSeriesItem.Clone()
   at Telerik.Charting.ChartSeries.CopyItems(ChartSeries originalSeries)
   at Telerik.Charting.ChartSeries.CloneSeries()
   at Telerik.Charting.RenderEngine.InitializeChartElements()
   at Telerik.Charting.Chart.GetImage(Int32 width, Int32 height)

how is this possible? I didn't found anything bizar in my code. I added a try catch around the code that fills the chart, but the error isn't triggered here, but in my main try catch of my program.

my code:

public partial class HistoricData : Form 
    { 
        public IOController TheIO { getset; } 
 
        public HistoricData() 
        { 
            InitializeComponent(); 
             
        } 
 
        public void FillData(List<ChartHistoric> days, string title) 
        { 
            try 
            { 
                rchrtHistoricData.DataSource = days; 
                rchrtHistoricData.ChartTitle.TextBlock.Text = title; 
                rchrtHistoricData.PlotArea.XAxis.DataLabelsColumn = "Month"
                rchrtHistoricData.PlotArea.XAxis.Appearance.LabelAppearance.RotationAngle = -45; 
                rchrtHistoricData.DataBind();     
            }catch(Exception ex) 
            { 
                Logging.Log.LogMessageToFile("HistoricData.cs -> FillData(List<ChartHistoric> days): " + ex.Message + ex.StackTrace); 
            } 
             
        } 
 
        public void FillTreeView(TreeNode overview) 
        { 
            trvMonths.Nodes.Clear(); 
            trvMonths.Nodes.Add(overview); 
        } 
 
        public void ClearChart() 
        { 
            rchrtHistoricData.DataSource = new List<ChartHistoric>();  
            rchrtHistoricData.DataBind(); 
        } 
 
        private void trvMonths_AfterSelect(object sender, TreeViewEventArgs e) 
        { 
            if(trvMonths.SelectedNode == nullreturn
 
            //ClearChart(); 
 
            //get the selected historic data for this month or whole year. 
            //data for the whole year 
            if(trvMonths.SelectedNode.Tag.Equals("1")) 
            { 
                FillData(TheIO.GetDataChartHistoricYear(), "Month view"); 
            } 
 
            if(trvMonths.SelectedNode.Tag.Equals("2")) 
            { 
                FillData(TheIO.GetDataChartHistoricMonth(trvMonths.SelectedNode.Text), "Week view"); 
            } 
        } 
    }



The function TheIO.GetDataChartHistoricMonth or TheIO.GetDataChartHIstoricYear are returning a list of ChartHistoric

public class ChartHistoric 
    { 
        public ChartHistoric(string _month, int _days) 
        { 
            month = _month; 
            days = _days; 
        } 
        private string month; 
        public string Month 
        { 
            get { return month; } 
            set { month = value; } 
        } 
        private int days; 
        public int Days 
        { 
            get { return days; } 
            set { days = value; } 
        } 
    } 

Thanks a lot

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gerbrand
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answered on 06 Nov 2009, 01:49 PM
Okay
I think I know where the crash happens.
When in my main form a treenode is triggered, the historicdata view is being reloaded. So the treeview on that form is reloaded and I'm clearing the chart from his datasource. Now I think that is the problem, I clear the datasource badly.

public void ClearChart() 
        { 
            rchrtHistoricData.DataSource = new List<ChartHistoric>(); 
            rchrtHistoricData.DataBind(); 
        } 

What is the best way to clear the datasource?
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Dwight
Telerik team
answered on 11 Nov 2009, 12:11 PM
Hi gerbrand,

To clear the data in the RadChart use:
this.radChart1.Clear();
this.radChart1.Refresh();

Let me know if you experience further issues with your scenario. Any sample application that we can debug would be helpful.

Sincerely yours,
Evtim
the Telerik team

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gerbrand
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answered on 13 Nov 2009, 10:22 AM
Before you posted the answer, I had already found this in the documentation after reading it a little bit better.

Since then I didn't had any issues anymore.

Thanks a lot
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gerbrand
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gerbrand
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Dwight
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