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Capturing the DataPoint which triggered a mouse event in a Stacked BarChart

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This is a migrated thread and some comments may be shown as answers.
Tanja
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Tanja asked on 14 Nov 2013, 02:27 PM
Hi,

We are trying to display data for a particular DataPoint which triggered a mouse event in a label but we are not having too much luck with it as we keep getting the entire BarSeries, not the actual DataPoint, passed into the event.

Here is a recap of what we are trying to achieve:

- a Stacked BarChart has two bar series ("Events" and "NonEvents" in the example) which are populated through a binding.
- there are three categories displayed: "G1", "G2" and "G3".
- on mouse over event of "G3"  bar we would like to display text "G3" on a label which is not a part of the chart.

Any ideas on this?

Best regards,
Tanja Risovic


Code:

  public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            
            var dataModel = new List<ViewDataModel>();

            var dataModel1 = new ViewDataModel();
            dataModel1.Events = 151;
            dataModel1.NonEvents = 24;
            dataModel1.GroupID = "1";
            dataModel1.GroupLabel = "G1";
           

            dataModel.Add(dataModel1);


            var dataModel2 = new ViewDataModel();
            dataModel2.Events = 4132;
            dataModel2.NonEvents = 529;
            dataModel2.GroupID = "2";
            dataModel2.GroupLabel = "G2";
          

            dataModel.Add(dataModel2);

            var dataModel3 = new ViewDataModel();
            dataModel3.Events = 1832;
            dataModel3.NonEvents = 109;
            dataModel3.GroupID = "3";
            dataModel3.GroupLabel = "G3";
           

            dataModel.Add(dataModel3);

            BarChartPercentage.DataContext = dataModel;         

                    }

        private void BarSeries_MouseEnter(object sender, MouseEventArgs e)
        {

            this.label.Content = ???; //We would like to show the GroupLabel of the DataPoint which triggered the mouse event, for example "G3"
      
        }

    }

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Petar Marchev
Telerik team
answered on 19 Nov 2013, 08:17 AM
Hi Tanja,

There are a few options you have. One is to set a PointTemplate for the bars of the series and set an element in the template with a MouseEnter handler. Another option is to use the series' MouseEnter and find the bar underneath the mouse by hit testing:
var result = VisualTreeHelper.HitTest((Visual)sender, e.GetPosition(null));
var bar = result.VisualHit as Border;
var dp = bar.DataContext as CategoricalDataPoint;

I hope this helps.

Regards,
Petar Marchev
Telerik
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Tanja
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Petar Marchev
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