Use Callout as Thumb ToolTip in RadSlider
The RadCallout can be easily used as a tooltip for the RadSlider control. To do that, we can use the AutoToolTipContentTemplate property of the RadSlider to place the RadCallout inside the Thumb ToolTip. Then we need to remove the Border of the ToolTip and make it transparent so that only the content (RadCallout) is visible. The code snippet in Example 1 demonstrates this approach.
Example 1: Callout as a ToolTip for RadSlider Thumb
<telerik:RadSlider AutoToolTipPlacement="TopLeft" Minimum="0" Maximum="100" LargeChange="5" SmallChange="1" VerticalAlignment="Center" HorizontalAlignment="Center" Width="500" >
<telerik:RadSlider.ThumbToolTipStyle>
<Style TargetType="ToolTip">
<Setter Property="BorderThickness" Value="0"/>
<Setter Property="Background" Value="Transparent"/>
</Style>
</telerik:RadSlider.ThumbToolTipStyle>
<telerik:RadSlider.AutoToolTipContentTemplate>
<DataTemplate>
<telerik:RadCallout Margin="5 5 5 10" >
<TextBlock Text="{Binding ., StringFormat=N2}" />
</telerik:RadCallout>
</DataTemplate>
</telerik:RadSlider.AutoToolTipContentTemplate>
</telerik:RadSlider>