Why's MVVMLight's message sent in vain?

Dear @brminnick, after reading #35, I’d like to ask if you’d elaborate on this a bit further? Because after watching your YT video, I implemented my commands (unifying your awesome IAsyncCommand with customer given requirement of using MVVMLight’s RelayCommand) like this:

public IAsyncCommand<string> SaveCommand => _save ?? (_save = new AsyncRelayCommand<string>(async title =>
  {
    await Task.WhenAll(DataService.UpdateTitle(title), CloseDialog(EDITOR_TITLE)).ConfigureAwait(false);
    Messenger.Default.Send(new TitleFinishedMessage(title));
  },
  title => !string.IsNullOrWhiteSpace(title),
  async exception => await ShowError("Title update failed.", exception).ConfigureAwait(false)));

And that’s because, using it like

await Task.WhenAll(DataService.UpdateTitle(title), CloseDialog(EDITOR_TITLE, new TitleFinishedMessage(title)))
          .ConfigureAwait(false);

with a centralized Messenger.Default.Send(message) inside CloseDialog() still sends the message, but in vain then.

I’ve already verified it’s not because of using continueOnCapturedContext’s value for MVVMLight’s constructors keepTargetAlive parameter, too: passing true instead (ignoring potential memory leak for this) still doesn’t fix the “message in vain” problem.

Can you help me, understanding this mystery?

[Eagle3386]

I’ll try to boil it down to kinda POC, but due to sprint commitments, that might take until Friday.

To minimize your need to dig deep while still obeying given business secrets constraints, I hope “view + viewmodel + faked data service (i. e. fixed values instead of an actual WebAPI service)” will still reproduce the bug - or at least outline how it’s working in real code…

Keep your fingers crossed on this one! 😉

[brminnick]

I appreciate the kind words!

Are you able to provide a reproduction sample? I’d be happy to dig into the code.