Ticks and Tick frequency

The Ticks property allows you to place marks(ticks) along the track in a non-uniform manner, unlike the TickFrequency property which places the ticks on equal intervals. The Ticks property is of type DoubleCollection and its default value is null. This property has to be combined with setting TickPlacement to something different than None.

<telerik:RadSlider Maximum="10" Ticks="3,5,7" TickPlacement="TopLeft" /> 

RadSlider radSlider1 = new RadSlider(); 
radSlider1.Maximum = 10; 
DoubleCollection tickCollection = new DoubleCollection(); 
tickCollection.Add(3); 
tickCollection.Add(5); 
tickCollection.Add(7); 
radSlider1.Ticks = tickCollection; 
radSlider1.TickPlacement = TickPlacement.TopLeft; 
LayoutRoot.Children.Add(radSlider1); 

Dim radSlider1 As New RadSlider() 
radSlider1.Maximum = 10 
Dim tickCollection As New DoubleCollection() 
tickCollection.Add(3) 
tickCollection.Add(5) 
tickCollection.Add(7) 
radSlider1.Ticks = tickCollection 
radSlider1.TickPlacement = TickPlacement.TopLeft 
LayoutRoot.Children.Add(radSlider1) 

The TickFrequency property on the other hand allows you to place marks(ticks) along the track in a uniform manner. On the example bellow, since the Maximum is 10 and the TickFrequency is 2, this means that there will be tick marks at 0, 2, 4, 6, 8 and 10.

<telerik:RadSlider Maximum="10" TickFrequency="2" TickPlacement="BottomRight" />