ToolTip on LegendLabel Silverlight RadChart

[siva]

My Silverlight Rad Chart Legend label content is too length, I want to display a custom legend label and ToolTip to show the entire legend name.Is it possible. How i can do that thanks in advance. It is very urgent

Thanks & Regards
Siva

[Missing User]

Hello siva,

You can set a custom label via the SeriesMapping as following:

SeriesMapping.LegendLabel = "Label Text";

or you can manually generate legend items:

radChart.DefaultView.ChartLegend.UseAutoGeneratedItems = false;
ChartLegendItem item1 = new ChartLegendItem();
item1.Label = "Item 1";
radChart.DefaultView.ChartLegend.Items.Add( item1 );

More information can be found in this help topic.

Basically, to display a tooltip over a legend item is not supported in the control out of the box. However, you can try the following approach:

private void radChart_DataBound(object sender, ChartDataBoundEventArgs e)
{
    var dataSeries = radChart.DefaultView.ChartArea.DataSeries;
    for (int i = 0; i < dataSeries.Count; i++)
    {
        string toolTip = "custom text";

        ChartLegendItem legendItem = (radChart.DefaultView.ChartLegend as ItemsControl).Items[i] as ChartLegendItem;
        ToolTipService.SetToolTip(legendItem, toolTip);
    }
}

I hope this helps.


Greetings,

Polina

the Telerik team

[Jonam]

Hello Polina,

your approach for the tooltip works for me only if the legend is set to dataseries level. Is it possible to set the tooltip if the legend is set to item level?

kind regards,

Jonam

[Petar Marchev]

Hi Jonam,

You can update the code to have the items count in mind:

private void radChart_DataBound(object sender, ChartDataBoundEventArgs e)
{
 var dataSeries = radChart.DefaultView.ChartArea.DataSeries;
 int itemsCount = (radChart.DefaultView.ChartLegend as ItemsControl).Items.Count;
 for (int i = 0; i < itemsCount; i++)
 {
  string toolTip = "my tool tip text";

  ChartLegendItem legendItem = (radChart.DefaultView.ChartLegend as ItemsControl).Items[i] as ChartLegendItem;
  ToolTipService.SetToolTip(legendItem, toolTip);
 }
}

Another approach can be to retemplate the LegendItem:

this.radChart.DefaultView.ChartArea.Legend.LegendItemStyle = this.Resources["ChartLegendItemStyle"] as Style;

<Style x:Key="ChartLegendItemStyle" TargetType="telerik:ChartLegendItem">
 <Setter Property="Template">
  <Setter.Value>
   <ControlTemplate TargetType="telerik:ChartLegendItem">
    <TextBlock x:Name="PART_TextBlock"
      Grid.Column="1"
      Foreground="{TemplateBinding Foreground}"
      Margin="{TemplateBinding Margin}"
      Padding="{TemplateBinding Padding}"
      Text="{TemplateBinding Label}"
      ToolTipService.ToolTip="{Binding DataItem}" />
   </ControlTemplate>
  </Setter.Value>
 </Setter>
</Style>

Here the DataItem is the underlying business object and you have access to all of its properties. Here you can find the full LegendItem style.

Kind regards,
Petar Marchev
the Telerik team