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ToolTip

Updated on Sep 23, 2026

The RadHeatMap control provides a tooltip behavior which can be used to visualize arbitrary information related to a data point. The ToolTip functionality is disable by default. To enable it, you need to set ShowToolTips property of the RadHeatMap to true.

Example 1: Enabling the ToolTip behavior of the RadHeatMap

XAML
<telerik:RadHeatMap ShowToolTips="True" />

Customizing the Tooltip

To customize the apperance of the tooltip you can use the HeatMapToolTipSettings propertyo of RadHeatMap. For demonstration purposes we will use a simple class that will represent one cell of the RadHeatMap control. This class will expose three properties:

  • Row: А string property which gets or sets the row name of the corresponding cell.
  • Column: А string property which gets or sets the column name of the corresponding cell.
  • Value: Аn integer property which gets or sets the value of the corresponding cell.

Example 2: Creating the model

C#
public class TempInfo
{
    public int Year { get; set; }
    public string Month { get; set; }
    public double Temperature { get; set; }
}
VB.NET
   Public Class TempInfo
	Public Property Year As Integer
	Public Property Month As String
	Public Property Temperature As Double
End Class

To fill the RadHeatMap with sample data we can create a list of TempInfo objects and set it as DataContext of the control.

Example 3: Populating the RadHeatMap control

C#
public partial class MainWindow : Window
{
    public MainWindow()
    {
        this.InitializeComponent();
        this.PrepareData();
    }

    private void PrepareData()
    {
        int year = 2018;
        string[] months = new string[6] { "Jan", "Feb", "Mar", "Apr", "May", "Jun" };
        var randomNumberGenerator = new Random();

        var source = new ObservableCollection<TempInfo>();
        for (int i = 0; i < months.Length; i++)
        {
            for (int k = 0; k < 6; k++)
            {
                var info = new TempInfo() { Year = year + k, Month = months[i], Temperature = randomNumberGenerator.Next(10, 300) };
                source.Add(info);
            }
        }

        this.DataContext = source;
    }
}
VB.NET
   Public Partial Class MainWindow
	Inherits Window

	Public Sub New()
		Me.InitializeComponent()
		Me.PrepareData()
	End Sub

	Private Sub PrepareData()
		Dim year As Integer = 2018
		Dim months As String() = New String(5) {"Jan", "Feb", "Mar", "Apr", "May", "Jun"}
		Dim randomNumberGenerator = New Random()
		Dim source = New ObservableCollection(Of TempInfo)()

		For i As Integer = 0 To months.Length - 1

			For k As Integer = 0 To 6 - 1
				Dim info = New TempInfo() With {
					.Year = year + k,
					.Month = months(i),
					.Temperature = randomNumberGenerator.[Next](10, 300)
				}
				source.Add(info)
			Next
		Next

		Me.DataContext = source
	End Sub
End Class

After having the sample data ready, we can go in the XAML code and define the RadHeatMap and the ToolTipSettings.

Example 4: Customizing the ToolTip

XAML
<telerik:RadHeatMap ShowToolTips="True" CellBorderColor="Black" CellBorderThickness="1" >
    <telerik:RadHeatMap.ToolTipSettings>
        <telerik:HeatMapToolTipSettings>
            <telerik:HeatMapToolTipSettings.ToolTipTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal" Background="White">
                        <TextBlock Text="Value: " FontSize="12"/>
                        <TextBlock Text="{Binding Value}" FontSize="12"/>
                    </StackPanel>
                </DataTemplate>
            </telerik:HeatMapToolTipSettings.ToolTipTemplate>
        </telerik:HeatMapToolTipSettings>
    </telerik:RadHeatMap.ToolTipSettings>
    <telerik:RadHeatMap.Definition>
        <telerik:CategoricalDefinition x:Name="categoricalDefinition" ItemsSource="{Binding}"
								RowGroupMemberPath="Year" 
								ColumnGroupMemberPath="Month" 
								ValuePath="Temperature" />
    </telerik:RadHeatMap.Definition>
</telerik:RadHeatMap>

Figure 1: RadHeatMap with customized ToolTip

RadHeatMap with selection enabled

See Also

In this article
Customizing the TooltipSee Also
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