如何通过基于XAML的数据绑定访问导航属性？

I'm attempting to learn WPF and MVVM and struggling with some databinding at the moment. I have a ComboBox that contains an observable collection of Projects, and a TextBox which is bound to the SelectedItem of the ComboBox and displays an EmployeeID value. I want to instead display the employee name that corresponds to the EmployeeID value, via a navigation property if possible, but not sure how to modify the XAML to allow for that.I'm attempting to learn WPF and MVVM and strugg