How to inject MonoBehaviour class to non Monobehaviour in Unity3d with zenject?

Question

I want to organize my code as well as I can, but I have some trouble with its organization. I try to use SOLID principles and make separate entities. I want to use MVVM to view (unity-weld as well), and DI container (zenject as well).

It's my first project and I'm trying to organize code.

My question is how to inject LoginViewModel into LoginController as static class using zenject container from GameInstaller class.

[Binding]
public class LoginViewModel : MonoBehaviour, INotifyPropertyChanged
{

    private string _username = "";
    private string _passsword = "";
    private string _errorMessage = "";
    private bool _autologin = false;

    [Inject]
    private LoginController _loginController;

    [Binding]
    public string Username {
        get
        {
            return _username;
        }
        set
        {
            if (_username == value)
            {
                return; // No change.
            }

            _username = value;
            Debug.Log($"SET username: {value}");
            OnPropertyChanged("Username");
        }
    }

    [Binding]
    public string Password {
        get
        {
            return _passsword;
        }
        set
        {
            if (_passsword == value)
            {
                return; // No change.
            }

            _passsword = value;
            Debug.Log($"SET password: {value}");
            OnPropertyChanged("Password");
        }
    }

    [Binding]
    public bool Autologin {
        get
        {
            return _autologin;
        }
        set
        {
            if (_autologin == value)
            {
                return; // No change.
            }

            _autologin = value;
            Debug.Log($"SET autologin: {value}");
            OnPropertyChanged("Autologin");
        }
    }

    [Binding]
    public void LoginButtonClick()
    {
        Debug.Log("LoginButtonClick");

        _loginController.Login(this);
        //ErrorMessage = "blabla";
    }

    [Binding]
    public string ErrorMessage
    {
        get
        {
            return _errorMessage;
        }
        set
        {
            if (_errorMessage == value)
            {
                return; // No change.
            }

            _errorMessage = value;
            Debug.Log($"SET errorMessage: {value}");
            OnPropertyChanged("ErrorMessage");
        }
    }

    /// <summary>
    /// Event to raise when a property's value has changed.
    /// </summary>
    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

public class LoginController
{
    private readonly ApiController _apiController;

    [Inject]
    private readonly LoginViewModel _loginViewModel;

    public LoginController(ApiController apiController)
    {
        _apiController = apiController;
    }

    public void Login(LoginViewModel loginViewModel)
    {
        try
        {
            string userJson = _apiController.PostLogin(loginViewModel.Username);

            _loginViewModel.ErrorMessage = "bla bla trololo";
            Debug.Log(userJson);
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
}

public class GameInstaller : MonoInstaller
{
    [Inject]
    Settings _settings = null;

    public override void InstallBindings()
    {
        InstallViewModels();
        InstallServices();
        InstallSignals();
        InstallControllers();
    }

    private void InstallViewModels()
    {
        Container.Bind<LoginViewModel>().AsSingle();
    }

    private void InstallControllers()
    {
        Container.Bind<LoginController>().AsSingle().NonLazy();
        Container.Bind<ApiController>().AsSingle().NonLazy();
    }

    private void InstallServices()
    {
    }

    private void InstallSignals()
    {
    }

    [Serializable]
    public class Settings
    {
    }
}

Answer 1

Let's start from here: https://unitylist.com/p/ja3/Unity-MVVM

A ViewModel (or VM) is what holds the data that will be presented on a view. It contains all the properties that can be bound to view elements. All ViewModels inherit from INotifyPropertyChanged which alerts the system when data changes and a UI element needs to be updated.

Since the ViewModel is in it's essence a simple object and not a service, I argue that it does not need go be injected anywhere.

What you could do, is inject a Factory and get your ViewModel from it.

In your code you are trying to inject the controller into your ViewModel and not the other way round.