"Unknown class ABC in Interface Builder file" AND "This class is not key-value compliant..."

Issue

I am attempting to set some properties of my ViewController via the User Defined Runtime Attributes section in XCode and running in to a few issues.

Firstly when the ViewController is instantiated (by a segue in my storyboard) I get the following in the output window:

Unknown class FlyoutViewController in Interface Builder file.

Secondly, I get the following error:

Objective-C exception thrown. Name: NSUnknownKeyException Reason: [UIViewController 0x7fdc1450> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key topViewControllerStoryboardId.

I have read the troubleshooting guide and nothing helped. The only part that stood out for me was:

the types containing the above code must be a subclass of NSObject

Although I fail to see how that is possible when subclassing UIViewController?

For reference here is the relevant parts of my code:

[Register("FlyoutViewController")]
public partial class FlyoutViewController : UIViewController, IUIViewControllerContextTransitioning, IUIViewControllerTransitionCoordinator, IUIViewControllerTransitionCoordinatorContext
{
    public FlyoutViewController(IntPtr handle) : base(handle) 
    {
       // Stuff here
    }

    [Export("topViewControllerStoryboardId:", ArgumentSemantic.Retain)]
    public NSString TopViewControllerStoryboardId { get; set; }

    [Export("underLeftViewControllerStoryboardId:", ArgumentSemantic.Retain)]
    public NSString UnderLeftViewControllerStoryboardId { get; set; }

    [Export("underRightViewControllerStoryboardId:", ArgumentSemantic.Retain)]
    public NSString UnderRightViewControllerStoryboardId { get; set; }

    // More stuff...
}

In the properties of the ViewController in the storyboard I have set the class to FlyoutViewController and added the following runtime attributes:

topViewControllerStoryboardId | String | FeedNavigationController
underLeftViewControllerStoryboardId | String | MenuViewController

Can anyone tell me where I am going wrong with this?

Thanks in advance.

Solution

The problem is that you are implementing two interfaces that have at least two identical members: IUIViewControllerTransitionCoordinatorContext and IUIViewControllerContextTransitioning.

This is the output I am getting, prior to the "...this class is not key value coding-compliant for the key topViewControllerStoryboardId" message:

Cannot register more than one interface method for the method 'XcodeAttrController.MyController.get_ContainerView' (which is implementing 'MonoTouch.UIKit.IUIViewControllerTransitionCoordinatorContext.get_ContainerView' and 'MonoTouch.UIKit.IUIViewControllerContextTransitioning.get_ContainerView').

Note that my controller here is named "MyController" :).

Implement one of the interfaces in another object and use that one instead.

Answered By - Dimitris Tavlikos