ASP.NET Charting Pie Chart - both inside and outside label per slice

Question

In an existing applications (web forms, but the underlying Microsoft Charting stack is basically the same for winforms/webforms/razor charts) I have Pie Charts, with for each slice the following business data:

Value
Label
Color (used for categorization, same color for multiple slices)

The requirement is a Chart that has all information layout out in one chart like this (mockup):

Using the CustomProperties on the Series/Points I can display each datapoint with either an Inside

Or an Outside Label:

But not both. Can I somehow trick the Pie Chart into displaying both an inside and outside label for each data point?

I realize that this is an edge case (normally you'd use legend+color to visualize this, but we already use color to categorize). I'd rather avoid rendering to a bitmap first and manually rendering the label texts on there (because there are mechanisms in place to stream the charts to both web pages and generated documents).

jsanalytics jsanalytics · Accepted Answer · 2017-11-19T15:18:29

Create two series and two chart areas and superimpose them:

ASPX:

<asp:Chart ID="Chart1" runat="server">
    <series>
        <asp:Series ChartType="Pie" 
            Name="Series1" 
            CustomProperties="PieLabelStyle=Inside, PieStartAngle=270" 
            BorderColor="White" 
            ChartArea="ChartArea1">
        </asp:Series>
        <asp:Series ChartType="Pie" 
            Name="Series2" 
            CustomProperties="PieLabelStyle=Outside, PieStartAngle=270" 
            ChartArea="ChartArea2">
        </asp:Series>
    </series>
    <chartareas>
        <asp:ChartArea Name="ChartArea1" >
            <InnerPlotPosition Height="95" Width="45.98404" X="27.00798" Y="2.50000072" />
        </asp:ChartArea>
        <asp:ChartArea Name="ChartArea2" 
            AlignWithChartArea="ChartArea1"
            AlignmentOrientation="All"
            BackColor="Transparent">
            <InnerPlotPosition Height="95" Width="45.98404" X="27.00798" Y="2.50000072" />
        </asp:ChartArea>
        </chartareas>
</asp:Chart>

CS:

protected void Page_Load(object sender, EventArgs e)
{
    List<MyDataModel> data = new List<MyDataModel> {
        new MyDataModel { Color = Color.LightBlue, Label = "Value 1", Value = 100 },
        new MyDataModel { Color = Color.LightBlue, Label = "Value 2", Value = 100 },
        new MyDataModel { Color = Color.LightBlue, Label = "Value 3", Value = 100 },
        new MyDataModel { Color = Color.Blue, Label = "Value 4", Value = 100 },
        new MyDataModel { Color = Color.Blue, Label = "Value 5", Value = 400 },
    };

        foreach (MyDataModel dm in data)
        {
            Chart1.Series[0].Points.Add(new DataPoint
            {
                Color = dm.Color,
                Label = dm.Value.ToString(),
                YValues = new double[] { dm.Value }
            });

            Chart1.Series[1].Points.Add(new DataPoint
            {
                Color = Color.Transparent,
                Label = dm.Label,
                YValues = new double[] { dm.Value }
            });
        }
}

ASP.NET Charting Pie Chart - both inside and outside label per slice

1 Answers