In the Code-behind, you will find the Click handler, where we use a couple of lines of code to get the binding from the destination control and then call the Update Source() method on it.
The second Text Box uses the Lost Focus value, which is actually the default for a Text binding.
Having said that, personally, I prefer things to happen in code when I tell them to, and not at some undefined and unpredictable point in the future; so, to unsubscribe: Because `IMvx Messenger` is registered as a singleton, once you resolve it, you should be able to publish this from anywhere.
The Menu View Model calls a service that creates the game world. First step is to add the progress bar to the screen that you want to update: (Warning: MVVM Cross specific) A caveat here; if you use something like `Register Type` to register the messenger object, that will also (appear to) work.
It then calls the Main Page View Model to display the main page. However, it won’t actually work; it will create a fresh instance of the messenger object each time.
Default is, obviously, the default value of the Update Source Trigger.
The other options are Property Changed, Lost Focus and Explicit.