Bug 38193 - OpenGLViewRenderer crashes when leaving the page.
Summary: OpenGLViewRenderer crashes when leaving the page.
Alias: None
Product: Forms
Classification: Xamarin
Component: iOS ()
Version: 2.0.0
Hardware: PC Mac OS
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2016-01-29 17:53 UTC by Andy
Modified: 2016-04-25 16:25 UTC (History)
4 users (show)

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

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Description Andy 2016-01-29 17:53:41 UTC
We tried switching from Xamarin.Forms 1.5.1 to XamarinForms . We have an OpenGLView that is on its own page. When we leave that page to go back to the main page, we get a crash.

Object reference not set to an instance of an object  at Xamarin.Forms.Platform.iOS.OpenGLViewRenderer.OnElementChanged (Xamarin.Forms.Platform.iOS.ElementChangedEventArgs`1 e) [0x0000e] in <filename unknown>:0 
  at Xamarin.Forms.Platform.iOS.VisualElementRenderer`1[TElement].SetElement (Xamarin.Forms.Platform.iOS.TElement element) [0x00118] in <filename unknown>:0 
  at Xamarin.Forms.Platform.iOS.VisualElementRenderer`1[TElement].Dispose (Boolean disposing) [0x0007b] in <filename unknown>:0 
  at Xamarin.Forms.Platform.iOS.ViewRenderer`2[TView,TNativeView].Dispose (Boolean disposing) [0x00000] in <filename unknown>:0 
  at Xamarin.Forms.Platform.iOS.OpenGLViewRenderer.Dispose (Boolean disposing) [0x00044] in <filename unknown>:0 
  at Foundation.NSObject.Dispose () [0x00000] in /Users/builder/data/lanes/2377/73229919/source/maccore/src/Foundation/NSObject2.cs:130 
  at Xamarin.Forms.Platform.iOS.Platform.DisposeModelAndChildrenRenderers (Xamarin.Forms.Element view) [0x00038] in <filename unknown>:0 
  at Xamarin.Forms.Platform.iOS.Platform.HandleChildRemoved (System.Object sender, Xamarin.Forms.ElementEventArgs e) [0x00007] in <filename unknown>:0 
  at Xamarin.Forms.Element.OnDescendantRemoved (Xamarin.Forms.Element child) [0x00015] in <filename unknown>:0 
  at Xamarin.Forms.Element.OnChildRemoved (Xamarin.Forms.Element child) [0x00021] in <filename unknown>:0 
  at Xamarin.Forms.VisualElement.OnChildRemoved (Xamarin.Forms.Element child) [0x00000] in <filename unknown>:0 
  at Xamarin.Forms.Page.OnInternalRemoved (Xamarin.Forms.VisualElement view) [0x00013] in <filename unknown>:0 
  at Xamarin.Forms.Page.InternalChildrenOnCollectionChanged (System.Object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00022] in <filename unknown>:0 
  at System.Collections.ObjectModel.ObservableCollection`1[T].OnCollectionChanged (System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00012] in /Users/builder/data/lanes/2377/73229919/source/mono/external/referencesource/System/compmod/system/collections/objectmodel/observablecollection.cs:286 
  at System.Collections.ObjectModel.ObservableCollection`1[T].OnCollectionChanged (NotifyCollectionChangedAction action, System.Object item, Int32 index) [0x00000] in /Users/builder/data/lanes/2377/73229919/source/mono/external/referencesource/System/compmod/system/collections/objectmodel/observablecollection.cs:349 
  at System.Collections.ObjectModel.ObservableCollection`1[T].RemoveItem (Int32 index) [0x0002b] in /Users/builder/data/lanes/2377/73229919/source/mono/external/referencesource/System/compmod/system/collections/objectmodel/observablecollection.cs:203 
  at System.Collections.ObjectModel.Collection`1[T].Remove (System.Collections.ObjectModel.T item) [0x0002d] in /Users/builder/data/lanes/2377/73229919/source/mono/external/referencesource/mscorlib/system/collections/objectmodel/collection.cs:134 
  at Xamarin.Forms.NavigationPage+<PopAsyncInner>d__69.MoveNext () [0x00123] in <filename unknown>:0
Comment 1 Brandon Minnick 2016-02-08 22:44:00 UTC
Here's additional information about the app (from the customer)

What type of page navigation are you using?
MainPage is a NavigationPage. We go to the next page which has the OpenGLView using MainPage.Navigation.PushAsync

Is the OpenGLView nested inside of a view?
It is nested inside of of a view on the 2nd page.

Does the OpenGLView take up the whole screen?
No it is a square the full width of the screen.
Comment 2 Brandon Minnick 2016-02-10 23:28:20 UTC
Here's additional information about the app (from the customer)

We installed several of the versions of Xamarin.Forms.2.x to see if it was just a bug in the latest version. We went back 1 by 1. The first version where this crash happens is in

We are currently on

This is turning into a bigger issue for us because we need the ListViewCachingStrategy RecycleElement for an update we are working on.
Comment 3 Jason Smith [MSFT] 2016-03-10 18:38:22 UTC
Should be fixed in 2.2.0-pre1
Comment 4 Parmendra Kumar 2016-04-25 16:25:09 UTC
I have checked this issue with 2.2.0-pre1 and its working fine at my end. I am no getting crash with latest xamarin.forms package.

Hence closing this issue.

If you still facing same issue please feel free to reopen this issue.