MonoTouch 5 Error: "Failed to find selector setXxxxxx" after migrating to Xcode 4.2 and MonoDevelop 2.8

Question

I have an iPad project that has been under development in Xcode 3.2.6 / MonoTouch 4.2.x / MonoDevelop 2.6 and when I installed the Monotouch 5, MonoDevelop 2.8.1 and Xcode 4.2 the project compiled and run OK. But when I started to change the XIB files in Xcode 4.2 (adding outlets) I started to have some glitches:

1) App crashes and MonoDevelop in debug mode says the the views were not loaded because the view outlet was not set. I figured out that in Xcode 4.2 there is no need to create an outlet named "view" in the .h file and just need to connect the File Owner view to the view control in the designer. Correct?

2) The main problem and is not solved yet is that I get exceptions "Failed to find selector setXxxxx" where "xxxxx" is a name of an outlet for a UI control. It started to happen in ViewControllers that inherited from a base view controller, but as soon as I started to change other normal viewControllers I get the same type of errors. Any hints of what is wrong?

3) I have a controller that loads dynamically some views and that works fine. but when I set a property on one of this sub views outlets (like the Text of a UILabel) the value is set (on the debugger) but no change in the UI. The actions for example work fine. What could be wrong.

4) Any special settings in the XIB's that are needed in order to correctly under Xcode 4.2 to integrate well with MonoDevelop 2.8?

Help is much appreciated, I thought in going back to the previous set of tools and monotouch but I guess once the project was upgraded there is no way to go back without losing all the development done now.

Thanks, Pedro

EDIT: Beside the new clean attributed [Outlet] code generated by MonoTouch 5 (replacing lot of code previously generated), the significant difference is that before the partial class generated was public and now is private, this may be the source of my problem. Is there a way to generate public partial classes or protected?

EDIT 2: If I manually add the public keyword to the partial class and members generated by MonoTouch in designer.cs the selectors are generated behind the scenes and all works. This indicates that with the change from public to private partial class the bindings generation changed in MonoTouch 5, is it by design or bug? I would find it very strange that now its not possible to create a viewcontroller with outlets, subclasss it and the child viewcontroller cannot access the parent class outlets.

Answer 1

1) There is indeed a view outlet on the base UIViewController class, which is an Objective-C property. When using Interface Builder 3 with MonoTouch, IB often didn't allow connecting to the base view outlet so many users created their own in their custom subclasses. MonoDevelop 2.6 and older created these custom outlets as ivars (Objective-C fields), and apparently the UIKit runtime would connect the object to both versions of the outlet - both the custom ivar and the base property. MonoDevelop 2.8 generates the custom outlets as properties, which means that the redundant view outlet shadows the base view outlet, so the base view outlet is never set, and UIKit gets unhappy. You can fix this by removing the redundant custom view outlet - MD 2.8.2 will do this automatically.

2) Seems to be a bug with the way MonoTouch exports custom outlets that prevents connecting to custom outlets defined in base classes. A possible workaround is mentioned on the bug report.

3) The UI rendering won't update while your app is paused in the debugger, it'll update on the next mainloop iteration.

4) Nope.

5) The class accessibility should be controlled by the user class part, not the designer class part, so you can freely change it.