Bindable "Value" property in DataTrigger.cs

Often you want to bind also the value in a DataTrigger in XAML.

Example usage:

<DataTrigger Binding="{Binding ElementName=PART_StartSlider, Path=Value}"
    Value="{Binding RelativeSource={RelativeSource TemplatedParent},Path=Minimum}">

In this I only want to check if the value of a slider in a CustomControl reaches the minimum value of my defined "Minimum" DependenyProperty in my CustomControl.cs to show an indicator element in the ControlTemplate of the CustomControl in XAML.