Bug 28486 - notification selectors have 0 arguments
Summary: notification selectors have 0 arguments
Alias: None
Product: Xamarin.Mac
Classification: Desktop
Component: Library (Xamarin.Mac.dll) ()
Version: 1.12.0
Hardware: Macintosh Mac OS
: High normal
Target Milestone: 2.0.x
Assignee: Chris Hamons
Depends on:
Reported: 2015-03-27 05:44 UTC by Radu
Modified: 2015-04-21 06:52 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Radu 2015-03-27 05:44:52 UTC
My app has successfully used the following code:

public override void AwakeFromNib (){
  ganttChartView.EnclosingScrollView.ContentView.PostsBoundsChangedNotifications = true;
  NSNotificationCenter.DefaultCenter.AddObserver (this, new Selector ("boundsDidChangeNotification"), NSView.BoundsChangedNotification, ganttChartView.EnclosingScrollView.ContentView);

[Export ("boundsDidChangeNotification")]
public void BoundsDidChangeNotification (NSObject o){

Since 1.12 this doesn't work anymore. It results in System.AggregateException being thrown in the Main class at runtime. You can trace that and conclude that it is due to the parameter in the selector. Somehow, since 1.12 the selector must have no parameter. The workaround is to use some alternative version of the AddObserver  method.

Don't you think that this change is quite unexpected?
Comment 1 Timothy Risi 2015-03-27 12:56:54 UTC

It looks like the Export statement needs a colon at the end to indicate the parameter.  Our new registrar got more picky some syntax issues like that where the old one didn't have an issue with it.  I changed it to:

[Export ("boundsDidChangeNotification:")]
public void BoundsDidChangeNotification (NSObject o)

and was able to run the app successfully without getting the AggregateException.
Comment 2 Mohit Kheterpal 2015-04-21 06:52:49 UTC
As per comment 1, this issue is answered by Timothy Risi. So I am closing this issue by marking it as Verified.