Tick template

Changing the look of the tick marks can be done by setting the TickTemplate property, which is of type DataTemplate.

XAML

	<telerik:RadSlider Maximum="10" TickFrequency="2" TickPlacement="BottomRight">
	    <telerik:RadSlider.TickTemplate>
	        <DataTemplate>
	            <Grid>
	                <Ellipse Width="5" Height="5" Fill="Black" />
	            </Grid>
	        </DataTemplate>
	    </telerik:RadSlider.TickTemplate>
	</telerik:RadSlider>

If you want to display the numeric value of each tick, you have to add a TextBlock to the template and bind its Text property as shown in the example bellow:

XAML

	<telerik:RadSlider Maximum="10" TickFrequency="1" TickPlacement="Both">
	    <telerik:RadSlider.TickTemplate>
	        <DataTemplate>
	            <Grid>
	                <TextBlock Text="{Binding}" FontSize="11"/>
	            </Grid>
	        </DataTemplate>
	    </telerik:RadSlider.TickTemplate>
	</telerik:RadSlider>

More information how to use a value converter and display not only numeric values, can be found here.