Q: Xamarin custom controls, how do I add properties to display in the Xcode panel? I want to implement custom controls, but the official case is too limited, I can not know more. What I want to know now is that I want to add an attribute to my control, such as Title, which must be free to fill in the Xcode control properties panel.
My current learning document: https://developer.xamarin.com/guides/mac/user-interface/custom-controls/

A: As I noted when you also asked here:

So if you are referring to:
https://developer.xamarin.com/guides/ios/user_interface/designer/ios_designable_controls_walkthrough/#Adding_Design-Time_Properties
(since it contains UIImage), that is discussing Xamarin Studio's built
  in iOS designer. Xamarin.Mac does not have such a feature.
The Xcode way of doing this is via IBInspectable / IBDesignable
http://nshipster.com/ibinspectable-ibdesignable/
however, Xcode / Xamarin.Mac does not have support for this.

