App splash screen shows, OnCreate never called - dies with System.ArgumentNullException RRS feed

  • Question

  • User365372 posted


    A co-worker had Visual Studio lock up yesterday. After restarting everything, he cannot run any of our apps. He is debugging on Android using emulators.

    In each case, the app builds, deploys, and begins launching - the app splash screen image shows, but then it crashes out (application is in break mode) with the following exception:

    System.ArgumentNullException: 'Value cannot be null. Parameter name: key'

    There is no stack trace information available (beyond [external code])

    This appears to occur before OnCreate gets called, so it doesn't seem like a problem with our code.

    He has: - restarted VS - rebooted - deleted and re-created various android emulators - cleaned, deleted bin and obj folders (builds successfully) - cleared NuGet cache - updated VS from 16.6.4 to 16.6.5

    Other posts mention possible issues with XAML compilation - which we use, but the rest of the developers don't have any trouble.

    Does anyone have any idea what might have gone awry? We are running out of ideas.


    Thursday, July 23, 2020 3:07 PM

All replies

  • User74 posted

    As you have other developers I presume you are using version control? Try a fresh check out of the code to a new folder, does that build ok?

    Thursday, July 23, 2020 6:34 PM
  • User365372 posted

    He completely reset/rebuilt the folder where the project is, with no change in results. No change in the results. We are completely baffled.

    Thursday, July 23, 2020 8:01 PM