CardView: Crash in Foundation when sliding back and forth

I have experienced the below crash several times during testing when sliding items quickly back and forth with CarouselView. The crash happens with 1.6.3 and 1.6.4-pre. I have tested it in Simulators and with physical devices and I can repro with both. I have been using Visual Studio 2017 (I have not tested with VS4M yet):

Unhandled Exception:

Foundation.MonoTouchException: Objective-C exception thrown.  Name: NSGenericException Reason: *** Collection <CALayerArray: 0x600002ce3420> was mutated while being e
![capture](https://user-images.githubusercontent.com/28783954/47255399-da60c200-d470-11e8-9362-e1e18881849a.PNG)
numerated.
Native stack trace:
	0   CoreFoundation                      0x000000011110529b __exceptionPreprocess + 331
	1   libobjc.A.dylib                     0x0000000111e59735 objc_exception_throw + 48
	2   CoreFoundation                      0x0000000111101f7c __NSFastEnumerationMutationHandler + 124
	3   UIKitCore                           0x000000011bf0b279 -[UIView(Hierarchy) subviews] + 363
	4   UIKitCore                           0x000000011bf24887 -[UIView(CALayerDelegate) _wantsReapplicationOfAutoLayoutWithLayoutDirtyOnEntry:] + 57
	5   UIKitCore                           0x000000011bf25055 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1505
	6   QuartzCore                          0x0000000109a9bd3d -[CALayer layoutSublayers] + 175
	7   QuartzCore                          0x0000000109aa0bf7 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 395
	8   QuartzCore                          0x0000000109a19aa6 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 342
	9   QuartzCore                          0x0000000109a50c2a _ZN2CA11Transaction6commitEv + 576
	10  Spike.CarouselView.iOS              0x0000000103717a79 xamarin_dyn_objc_msgSend + 217
	11  ???                                 0x0000000136c4ecd0 0x0 + 5213842640
	12  ???                                 0x0000000136bf46f3 0x0 + 5213472499
	13  Spike.CarouselView.iOS              0x00000001035253c1 mono_jit_runtime_invoke + 1441
	14  Spike.CarouselView.iOS              0x000000010360bcff mono_runtime_invoke_checked + 127
	15  Spike.CarouselView.iOS              0x0000000103654c4a start_wrapper_internal + 602
	16  Spike.CarouselView.iOS              0x00000001036549c7 start_wrapper + 71
	17  libsystem_pthread.dylib             0x00000001137e333d _pthread_body + 126
	18  libsystem_pthread.dylib             0x00000001137e62a7 _pthread_start + 70
	19  libsystem_pthread.dylib             0x00000001137e2425 thread_start + 13

About this issue

Original URL
State: closed
Created 6 years ago
Comments: 22 (10 by maintainers)

Most upvoted comments

@aman720gupta hi

Have you tried latest version? Also, try to set MaxChildrenCount = 30 and DesiredMaxChildrenCount = 30

I’m using latest version but let me check with this values

aman720gupta on Feb 20, 2019

I think, this issue can go away with new releases )

AndreiMisiukevich on Feb 10, 2019

Yes, Alex’s control is not bug free but we’ve found it to be quite robust. There’s been a few issues but all within the source code (the latest version isn’t packaged yet so we’re running the source code). We found one GC/Dispose bug but we fixed that (and we will be forwarding it to Alex).

jonasrembratttetrapak on Dec 13, 2018

ok, funny, since I’ve started with Alex control and changed to this one, since I got to many errors with the other one, especially these NSGenericExceptions.

shoeIT on Dec 13, 2018

I also get this error now…@jonasrembratttetrapak did you find something to solve this ?

maybe its related to this: https://github.com/xamarin/Xamarin.Forms/issues/2087

shoeIT on Dec 13, 2018