Bug 44842 - OnBackPressed in FormsAppCompatActivity InvalidOperationException - "Sequence contains no elements" on Linq Last()
Summary: OnBackPressed in FormsAppCompatActivity InvalidOperationException - "Sequence...
Alias: None
Product: Forms
Classification: Xamarin
Component: Android ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: E.Z. Hart [MSFT]
Depends on:
Reported: 2016-09-28 19:01 UTC by aslclay
Modified: 2017-06-19 18:47 UTC (History)
4 users (show)

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

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Description aslclay 2016-09-28 19:01:32 UTC
App crashes any time the back button is pressed. It doesn't matter if the current page is the root of the navigation stack or farther down the stack. The ActionBar "up" button does work as expected.

at System.Linq.Enumerable.Last[TSource] (IEnumerable`1 source) [0x0007e] in <filename unknown>:0 
  at Xamarin.Forms.Platform.Android.AppCompat.Platform.HandleBackPressed (System.Object sender, System.EventArgs e) [0x00000] in C:\BuildAgent2\work\aad494dc9bc9783\Xamarin.Forms.Platform.Android\FormsApplicationActivity.cs:271 
  at (wrapper delegate-invoke) <Module>:invoke_bool_object_EventArgs (object,System.EventArgs)
  at Xamarin.Forms.Platform.Android.FormsAppCompatActivity.OnBackPressed () [0x00012] in C:\BuildAgent2\work\aad494dc9bc9783\Xamarin.Forms.Platform.Android\FormsApplicationActivity.cs:163 
  at Android.App.Activity.n_OnBackPressed (IntPtr jnienv, IntPtr native__this) [0x00009] in <filename unknown>:0 
  at (wrapper dynamic-method) System.Object:b63a2dfc-df9b-49b7-a944-0786ffc2ea73 (intptr,intptr)
Comment 1 E.Z. Hart [MSFT] 2016-10-03 22:12:57 UTC
Thank you for taking the time to submit the bug. We tried to reproduce the issue you reported but were unable given the description. If you could please attach a reproduction to the bug by starting with a clean Xamarin.Forms project and adding just the code necessary to demonstrate the issue, we would very much appreciate it.

For your convenience, we have created some reproduction best practices viewable here: https://gist.github.com/jassmith/92405c300e54a01dcc6d

Warm regards,

Xamarin Forms Team
Comment 2 Samantha Houts [MSFT] 2017-06-19 18:47:28 UTC
Because we have not received a reply to our request for more information we are closing this issue. If you are still encountering this issue, please reopen the ticket with the requested information. Thanks!