Radchart - Pie chart Legend not as expected

[pradip]

Hi

I was trying to generate the Pie chart. Everything was fine except the Legend. It is giving me - Item1, Item2 Item3 etc instead of actual item values... 

Have look at the code,

        Dim chaSer As New ChartSeries
        radChart.AddChartSeries(chaSer)
        radChart.ChartTitle.TextBlock.Text = "Polling Result"
        radChart.Skin = "WebBlue"
        radChart.Attributes.Add("Palette", "Colorful")
        getRespDt()

            chaSer.Type = ChartSeriesType.Pie
            chaSer.DefaultLabelValue = "#%"
            chaSer.Appearance.ShowLabels = True
         
      
        chaSer.DataYColumn = "Count"

        chaSer.Appearance.LegendDisplayMode = ChartSeriesLegendDisplayMode.ItemLabels

        radChart.DataSource = dtPoll
        radChart.DataBind()


        Response.ContentType = "image/png"
        radChart.Save(Response.OutputStream, ImageFormat.Jpeg)

Thanks,
Pradip

[Velin]

Hello pradip,

There are a couple of steps you need to do:

1. Register for the ItemDataBound event and set value to the Name property of each item. This value will be displayed in the legend. Here is the sample code:
   
   Copy Code

   <telerik:RadChart ID="RadChart1" runat="server" OnItemDataBound="ItemDataBound">
   
       public void ItemDataBound(object sender, ChartItemDataBoundEventArgs e)
       {
           e.SeriesItem.Name = dataSource.Rows[e.SeriesItem.Index]["LegendName column"].ToString();
       }

2. Set the series Appearance.LegendDisplayMode to ItemLabels. This instructs the legend to show labels for each item in the series.
   Copy Code

    <Series>
    <telerik:ChartSeries Appearance-LegendDisplayMode="ItemLabels" Type="Pie" DataYColumn="CurrentDrainPercentage" />
    </Series>

Where the "LegendNameColumn" string should be replaced with the name of the column from your data source that holds the legend labels. 

Best wishes,
Velin
the Telerik team

[Celeste]

I am experiencing the same issue. The chart is using a SqlDataSource but the 
SqlDataSource object has no .Rows property. Please identify the object type of your dataSource object or assist. Thank you.

[Velin]

Hi Celeste,

You can find the respective row from the data source using code like this:

public void ItemDataBound(object sender, ChartItemDataBoundEventArgs e)
{
    e.SeriesItem.Name = (e.DataItem as DataRowView).Row["Name"].ToString();
}

Where "Name" is actually column name used for legend labels.

Kind regards,
Ryan
the Telerik team

[Celeste]

Thank you, that helped!

[kamal]

i have a problem with pie chart legends

this is the code i have implemented :

PieSeriesDefinition lineDefinition = new PieSeriesDefinition();
lineDefinition.SeriesName = strElementName;                    
lineDefinition.LegendDisplayMode = LegendDisplayMode.SeriesLabel;

i have data for 2 elements, chart shows data for 2 elements but the color of both the elements is same, also it shows only one legend, it should have shown  2 legends.
i am using auto generated legends.
if i generate legends, how to color those legends to get the default colors as i am not changing the default colors of the chart area.

[Marbry]

The last example given retrieves the correct data, but it's not being displayed in the legend.

The example you gave doesn't seem to be right, why would you populate the name, then set the display mode to label?

Shouldn't there be a ChartSeriesLegendDisplayMode.ItemNames ?

 

[Ves]

Hello Marbry,

I agree, this is a bit misleading. The Name provides the value to display in the legend, while the Label provides the string for the label. In case you need them equal, you can populate them with the same values.

Kind regards,
Ves
the Telerik team

[marinus bosman]

[Deleted: Posted in Wriong Thread]