Question: Planning to rewrite a complex, UI-heavy app so that its model is as cross-platform as reasonably possible. The research / reading I've done makes sense conceptually, but in terms of the model sending messages to the controller in some sort of cross-platform approach, I'm not seeing what a best practices approach would entail.

For example, the Model is changed via the Controller making calls to the Model's API. But the Model is then responsible for informing clients of its data that a change has taken place, so it needs to broadcast that back to the Controller -- which needs to inform the View(s).

But messaging approaches are going to be different for a controller written in C# or Objective-C++, right? Would one use signal to connect to the Controller, which would use platform-specific message communication with the View(s)?

Is there a standard, lightweight template that sets up these best practices for the platform-independent model operations?

Answer: 
I had this issue when I opened a VS2017 project in VS2015, built the solution and then uploaded the DLLs.

Rebuilding it in VS2017 and re-uploading the DLLs fixed the issue.
None of these answers helped me since I created my `jsx` files in a weird way. My code was working in localhost mode but failed in production.

The fix for me was to go into the `csproj` file and change the file paths from `<None ...` to `<Content ...`