Telerik UI for Windows Phone by Progress

If you want to limit the user into choosing a numerical value from a specific range, you can simply do it by setting the MinValue and MaxValue properties. Here is an example.

<telerikInput:RadNumericUpDown x:Name="radNumericUpDown" VerticalAlignment="Center" MinValue="10" MaxValue="20" Value="10" />

This will prevent the user from selecting a value of this range.