Question

我的MasterPage当前使用事件驱动方法，如下所示：

MasterPage.xaml.cs

private void TapHome_Tapped(object sender, EventArgs e)
    {
        Detail = new NavigationPage(new HomePage());
        IsPresented = false;
    }

App.xaml.cs：

public App()
    {
        InitializeComponent();

        if (!string.IsNullOrEmpty(Preferences.Get(Constant.Setting_AccessToken, "")))
        {
            MainPage = new MasterPage();
        }
        else if (string.IsNullOrEmpty(Preferences.Get(Constant.Setting_UserEmail, "")) && 
            string.IsNullOrEmpty(Preferences.Get(Constant.Setting_Password, "")))
        {
            MainPage = new NavigationPage(new LoginPage());
        }

    }

由于我们尝试迁移到MVVM方法。我们试图更改代码：

MasterPage.xaml.cs

public MasterPage()
    {
        InitializeComponent();
        BindingContext = _viewModel = new MasterViewModel()
        {
            Navigation = Navigation
        };
        //IsPresented = false;
    }

MasterViewModel.cs：

public ICommand HomeCommand { get; private set; }

    public ICommand ActivitiesCommand { get; private set; }

    public ICommand ChangePasswordCommand { get; private set; }

    public ICommand LogoutCommand { get; private set; }

    public MasterViewModel()
    {
        HomeCommand = new Command(async () => await GoToHome());
        ActivitiesCommand = new Command(async () => await GoToActivities());
        ChangePasswordCommand = new Command(async () => await GoToChangePassword());
        LogoutCommand = new Command(async () => await Logout());
    }

    public async Task GoToHome()
    {
        // Attempt 1:
        // Navigation.PushAsync(new NavigationPage(new HomePage()));

        // Attempt 2:
        // Application.Current.MainPage = new NavigationPage(new HomePage());
    }

尝试了第一次尝试，我们在Android上出错- System.InvalidOperationException：Android上不全局支持PushAsync，请使用NavigationPage。

尝试了第二次尝试，并且工作正常，但单击后在主页或其他页面上没有导航。

有什么想法吗？

Answer 1

没关系。我们解决了这个问题：

public async Task GoToHome()
    {
        ((MasterDetailPage)Application.Current.MainPage).Detail = new NavigationPage(new HomePage());
        ((MasterDetailPage)Application.Current.MainPage).IsPresented = false;
    }

如何从MasterPage进行PushAsync？

1 个答案: