public RegisterViewModel(
     IRegisterService registerService,
     IDialogService dialogService,
     IKeyboardService keyboardService,
     IHelpYouService helpYouService)
 {
     this.registerService = registerService;
     this.dialogService   = dialogService;
     this.keyboardService = keyboardService;
     this.helpYouService  = helpYouService;
 }
    public LogInViewModel(
        ILogInService logInService,
        IDialogService dialogService,
        IKeyboardService keyboardService,
        IHelpYouService helpYouService)
    {
        this.logInService    = logInService;
        this.dialogService   = dialogService;
        this.keyboardService = keyboardService;
        this.helpYouService  = helpYouService;

        CallUsCommand       = new AsyncCommand(() => CallUsCommandd());
        DoLoginCommand      = new AsyncCommand(() => DoLoginCommandAsync());
        GoToRegisterCommand = new AsyncCommand(() => GoToRegisterCommandAsync());
    }