ChartControl - How to select a SeriesPoint when clicking the legend item label

Andre Wollny

created 7 years ago

Hello,

my goal is that a user can filter the data by clicking on a legend label
(just like selecting a series by clicking in the pie chart itself).

I am using a hit-test in the MouseClick-event which works fine.
The only downside is that there is no visual feedback that a series is "selected" / there is no highlighting-
just like when i click directly in the pie chart.

How can i achieve this via code?

Thank you!

selectSeri...sPoint.png

Answers approved by DevExpress Support

DevExpress Support Team

created 7 years ago

Hello,

To implement this task, I suggest you enable chart selection by setting the ChartControl.SelectionMode property to Single and ChartControl.SeriesSelectionMode to Point. To select the required point in code, use the ChartControl.SelectedItems property.
Should you have any further questions, feel free to contact us.

Show previous comments (4)

Andre Wollny 7 years ago

Hi,

thank you.

I cant use ChartControl.SelectedItems because the property is readonly and only a getter exists.

Andre Wollny 7 years ago

I can do something like:

C#
chartControl.SelectedItems.Clear();  
chartControl.SelectedItems.Add(hitInfo.SeriesPoint);

but the chart (or the series) itself gets not highlighted / repainted.

DevExpress Support Team 7 years ago

I have attached a sample project that illustrates the suggested approach. I hope it will be helpful.

T657508.zip

Andre Wollny 7 years ago

Thank you, an example like this is always a good idea.

When i click "your" button outside the control everything works fine.

When i do add this (like in my code) there is no visual selction:

C#
private void chartControl1_MouseClick(object sender, MouseEventArgs e)  
{  
    ChartHitInfo hitInfo = chartControl1.CalcHitInfo(e.Location);  

    if (hitInfo.InLegend && !hitInfo.InSeries)  
    {  
        if (hitInfo.SeriesPoint == null)  
        {  
            return;  
        }  

        // chartControl.ClearSelection();  
        chartControl1.SelectedItems.Add(chartControl1.Series[0].Points[0]);  
    }  
}

Although the selection changes

DevExpress Support Team 7 years ago

Hello,

Thank you for the clarification. To select the required point on the legend item label click, I suggest you turn-off the Chart selection by setting the SelectionMode property to None and modify your code in the following manner:

C#
private void chartControl1_MouseDown(object sender, MouseEventArgs e)  
{  
    ChartHitInfo hitInfo = chartControl1.CalcHitInfo(e.Location);  
    // if (hitInfo.InLegend && !hitInfo.InSeries) uncomment to select only by the labels click  
    {  
        if (hitInfo.SeriesPoint == null)  
            return;  
         chartControl1.ClearSelection();  
        chartControl1.SelectedItems.Add(chartControl1.Series[0].Points.FirstOrDefault(r => r.ArgumentX.NumericalArgument == hitInfo.SeriesPoint.NumericalArgument));  
    }  
}

Attached is the modified project. I hope it will be helpful.

T657508_2.zip

Andre Wollny 7 years ago

Thank you!

This one works like a a charm.

DevExpress Support Team 7 years ago

You are welcome! I am happy to hear that my assistance was helpful. Please feel free to contact us at any time.

Created: July 23, 2018 7:56 AM

Modified: July 27, 2018 6:53 AM

Platform: WinForms

Product: XtraCharts Suite

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ChartControl - How to select a SeriesPoint when clicking the legend item label

Answers approved by DevExpress Support

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