사실 이건 WPF에 대한거라 Dependency property이고 Xamarin에서는 Bindable property를 사용하면 된다.
https://msdn.microsoft.com/en-us/library/ms752914.aspx
https://msdn.microsoft.com/en-us/library/bb613563(v=vs.110).aspx
Recommendations and best practices for implementing MVVM and XAML/.NET applications
Don’t do that in the WPF Designer (Cider)!
: https://blogs.msdn.microsoft.com/jnak/2007/11/08/dont-do-that-in-the-wpf-designer-cider/
XAML Anti-Patterns: Code-Behind
: http://www.codemag.com/article/1505101
데이터 바인딩 개요
: https://msdn.microsoft.com/ko-kr/library/ms752347(v=vs.110).aspx
Getting Rid of Your Code Behind
: http://www.codemag.com/Article/1208031