[Bug] MainThread.BeginInvokeOnMainThread crashes on Windows if called too early

[tipa]

Description

If MainThread.BeginInvokeOnMainThread is called to early, it crashes with

System.InvalidOperationException: 'A method was called at an unexpected time.
Could not create a new view because the main window has not yet been created'

Steps to Reproduce

Execute MainThread.BeginInvokeOnMainThread in app constructor

Expected Behavior

No crash, exception is caught and code is executed on current thread

Actual Behavior

It crashes here:

Essentials/Xamarin.Essentials/MainThread/MainThread.uwp.cs

Line 16 in b018723

if (CoreApplication.MainView.CoreWindow == null)

Basic Information

• Version with issue: Xamarin.Essentials 1.3.1

Reproduction Link

App3.zip

[jamesmontemagno]

Hmmm, i'll give it a try. this is master: https://github.com/xamarin/Essentials/blob/master/Xamarin.Essentials/MainThread/MainThread.uwp.cs i wonder what isn't null.

[jamesmontemagno]

I see, it basically throws an exception when we check :(