Question

How does the ObjectiveC code below translate into MonoTouch?

@interface PSPDFBookmarkViewController : UITableViewController <PSPDFStyleable>
- (instancetype)initWithDocument:(PSPDFDocument *)document;
@property (nonatomic, weak) id<PSPDFBookmarkViewControllerDelegate> delegate;
@property (nonatomic, assign) BOOL isInPopover;
@end

• I don’t really know what to do with the instancetype thingy (what is this?)
• What is id<PSPDFBookmarkViewControllerDelegate>.
• What to do with the PSPDFStyleable?

This is what I think would be the result:

[BaseType(typeof(UITableViewController)]
    interface PSPDFBookmarkViewController
    {
    void InitWithDocument(PSPDFDocument document);
    [NullAllowed]
    PSPDFBookmarkViewControllerDelegate Delegate { get; set; }
    bool IsInPopover { get; set; }
    }

And what about this interface?

@interface PSPDFBookmarkViewController (SubclassingHooks)
- (void)createBarButtonItems;
@end

What is the (SubclassingHooks) about and what is its C# cousin?

Answer 1

Many questions… here’s a few answers:

ObjectiveC init* selectors are .NET constructors. So:

- (instancetype)initWithDocument:(PSPDFDocument *)document;

should be like:

[Export ("initWithDocument:")]
IntPtr Constructor (PSPDFDocument document);

and your other C# bindings are missing their [Export] attributes. E.g.

[Export ("isInPopover")]
bool IsInPopover { get; set; }

Other questions:

<PSPDFStyleable> is a Objective-C protocol, which is very similar to .NET interfaces. Now if you don’t need PSPDFStyleable then you do not have to bind it.

What is id<PSPDFBookmarkViewControllerDelegate>.

That’s an instance that implements PSPDFBookmarkViewControllerDelegate. You would normally bind this as PSPDFBookmarkViewControllerDelegate for the Delegate property and also add a WeakDelegate so any NSObject that implement the right selectors can be used. E.g.

[Export ("delegate", ArgumentSemantic.Assign)][NullAllowed]
NSObject WeakDelegate { get; set; }

[Wrap ("WeakDelegate")]
PSPDFBookmarkViewControllerDelegate Delegate { get; set; }

You’ll need to add Delegates=new string [] { "WeakDelegate" } to your [BaseType] attribute. Also add Events= if you want to turn the delegate members into events. E.g.

[BaseType (typeof (UITableViewController), Delegates=new string [] { "WeakDelegate" }, Events=new Type [] {typeof (PSPDFBookmarkViewControllerDelegate)})]

(SubclassingHooks) is an Objective-C category, which is very similar to .NET extensions methods. That requires a bit of manual bindings with the existing generator.

Finally make sure to read the binding documents that are available on Xamarin documentation portal. It’s not very complicated (your sample hits a lot of cases for very few lines) but there’s a lot of data to digest (even more if you do not know Objective-C very well).