Issue with DependencyProperty binding

Question

I created a small File Browser Control:

Answer 1

Do not ever set DataContext of UserControl inside usercontrol:

THIS IS WRONG:

this.DataContext = someDataContext;

because if somebody will use your usercontrol, its common practice to set its datacontext and it is in conflict with what you have set previously

Which one will be used? Well, it depends...

The same applies to Name property. you should not set name to UserControl like this:

because it is in conflict with

SOLUTION:
In your control, just use RelativeSource Mode=FindAncestor:

To your question on how are all those third party controls done: They use TemplateBinding. But TemplateBinding can be used only in ControlTemplate. http://www.codeproject.com/Tips/599954/WPF-TemplateBinding-with-ControlTemplate

In usercontrol the xaml represents Content of UserControl, not ControlTemplate/