There is a template:
<Window.Resources>
<ResourceDictionary>
<ControlTemplate x:Key="Class1">
<objs:Class1 FontSize="12" x:Name="class1"/>
</ControlTemplate>
</ResourceDictionary>
</Window.Resources>
It consists of a UserControl. I apply it like this:
<local:MyThumb Width="120" Height="70" x:Name="myThumb1" Canvas.Left="270" Canvas.Top="60" Template="{StaticResource Class1}"/>
The question is how to get this UserControl from the code and change its properties, such as Background for example.