How to redraw chart?

[hyojung kwon]

Hello,

In my application I draw LineSeries chart using WCF service.

Chart is drawn, once page is loaded for the first time and when user click refresh button, it gets new data using WCF service then is supposed to be redrawn.

However, when chart is redrawn by refresh button, LineSeries chart draws over old chart without clearing old chart.

I used following code to refresh chart.

       void server_GetGraphDataCompleted(object sender, GetGraphDataCompletedEventArgs e)

        {

            RadChart1.ItemsSource = null;

            List<GraphEntity> result = e.Result;

            RadChart1.ItemsSource = result;

        }

Whenever user click refresh button, chart is created over old one.

Can you tell me what I did wrong?

Thanks in advance

Kwon

[Vladimir Milev]

Hello hyojung kwon,

You are binding the chart correctly. Most probably the data returned in the second call to the service contains the old data as well and the chart correctly plots both series.

Best wishes,
Vladimir Milev
the Telerik team

[hyojung kwon]

I checked my code but data returned from service has same counts and same data.

Following is my code in silverlight behind code.

private ServiceReference.ServiceClient server;

public GraphDemo()

        {

            InitializeComponent();

         

            server = new ServiceReference.ServiceClient();

            server.GetGraphDataCompleted += new EventHandler<GetGraphDataCompletedEventArgs>(server_GetGraphDataCompleted);

            FillChartData();

        }

 private void FillChartData()

        {

                SeriesMapping sm2 = new SeriesMapping();

                sm2.SeriesDefinition = new LineSeriesDefinition();

                sm2.LegendLabel = "SpO2";

                ItemMapping im3 = new ItemMapping("SpO2Value", DataPointMember.YValue);

                ItemMapping im4 = new ItemMapping("ColumnTimeForXCategory", DataPointMember.XCategory);

                sm2.ItemMappings.Add(im3);

                sm2.ItemMappings.Add(im4);

                RadChart1.SeriesMappings.Add(sm2);

                

                server.GetGraphDataAsync();

}

void server_GetGraphDataCompleted(object sender, GetGraphDataCompletedEventArgs e)

        {

            RadChart1.ItemsSource = null;

            List<GraphEntity> result = e.Result; // returns same number of data from service

            RadChart1.ItemsSource = result;

        }

Is there any doubtable code up there?

Thanks in advance.

Kwon

[Nikolay]

Hello hyojung kwon,

It appears that the issue is related to what happens when clicking the Refresh button. In order to clear the older chart you need to clear the SeriesMappings and call FillChartData() again, as shown below :

private void RefreshButton_Click(object sender, RoutedEventArgs e)
       {
           RadChart1.SeriesMappings.Clear();
           this.FillChartData();
       }

Please, let us know if this works on your side as well.

Kind regards,
Nikolay
the Telerik team

[hyojung kwon]

Hello Nikolay

It is working well for me.
Thank you so much.

Regards
Kwon

[Niclas Junsved]

Hi!

How do I achieve "clear" as below in Q2 2010 version?

 

radChart.SeriesMappings.Clear();

 

Regards

Niclas