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Regarding this code in MonoTouch.UIKit.UIPanGestureRecognizer
public virtual PointF TranslationInView(UIView view)
if (view == null)
throw new ArgumentNullException("view");
My understanding is that I should be able to call this function with view == null to get the translation in the Window.
Created attachment 6137 [details]
Run the attached project and touch anywhere on the view to crash. Then change the gesture code (in AppDelegate.cs) to use the alternative implementation (directly calling "translationInView:" with a null view) to see that it works with null in Apple's code.
Thanks for the test case! It looks like a non-documented behaviour  but other API uses a similar trick, where a nil UIView means UIWindow.
I'll check for the other API in the type, e.g. velocityInView:, and fix this for the next maintenance release.
UIPanGestureRecognizer accepts null for UIView in SetTranslation, TranslationInView and VelocityInView methods.
Fixed in master / 7d2e3d361f20147789629c732e6f2b6029b05166
QA: unit tests added in the same revision
I have checked this issue on following builds:
Xamarin Studio : 4.2.4 (build 32)
Xamarin.iOS : 18.104.22.168 (Trial Edition)
Release ID: 402040032
Git revision: a160c35dac9ab9fd32eeadaa171216316d5a5133
Build date: 2014-03-12 13:55:08-04
Xamarin addins: a779416ceabd54981ce812771a4061c942e8b872
I have checked the signature of "TranslationInView(UIView view)" in "assembly browser" and I observed that now we are able to call this method with "view==null" to get the translation in the Window and it will not throw ArgumentNullException exception.
This issue is working fine. Hence, I am closing this issue.