在构造函数 VB.NET 中将共享 属性 值设置为 Me

Question

我尝试创建 Template10 UWP template 的 VB.NET 版本。

模板几乎准备就绪，但执行后我在 Shell.xaml.vb 文件中收到一条错误消息。这个class:

的原始C#代码

public sealed partial class Shell : Page
{
    public static Shell Instance { get; set; }
    public static HamburgerMenu HamburgerMenu => Instance.MyHamburgerMenu;
    Services.SettingsServices.SettingsService _settings;

    public Shell()
    {
        Instance = this;
        InitializeComponent();
        _settings = Services.SettingsServices.SettingsService.Instance;
    }

    public Shell(INavigationService navigationService) : this()
    {
        SetNavigationService(navigationService);
    }

    public void SetNavigationService(INavigationService navigationService)
    {
        MyHamburgerMenu.NavigationService = navigationService;
        HamburgerMenu.RefreshStyles(_settings.AppTheme, true);
        HamburgerMenu.IsFullScreen = _settings.IsFullScreen;
        HamburgerMenu.HamburgerButtonVisibility = _settings.ShowHamburgerButton ? Visibility.Visible : Visibility.Collapsed;
    }
}

和VB.NET中的转换版本：

Partial Public NotInheritable Class Shell
    Inherits Page

    Public Shared Property Instance As Shell
    Public Shared Property HamburgerMenu As HamburgerMenu = Instance.MyHamburgerMenu
    Public _settings As SampleApp.Services.SettingsServices.SettingsService

    Public Sub New()
        Instance = Me
        InitializeComponent()
        _settings = SampleApp.Services.SettingsServices.SettingsService.Instance
    End Sub

    Public Sub New(navigationService As INavigationService)
        Me.New()
        SetNavigationService(navigationService)
    End Sub

    Public Sub SetNavigationService(navigationService As INavigationService)
        MyHamburgerMenu.NavigationService = navigationService
        HamburgerMenu.RefreshStyles(_settings.AppTheme, True)
        HamburgerMenu.IsFullScreen = _settings.IsFullScreen
        HamburgerMenu.HamburgerButtonVisibility = If(_settings.ShowHamburgerButton, Visibility.Visible, Visibility.Collapsed)
    End Sub

End Class

执行的入口点是：

Public Sub New(navigationService As INavigationService)

异常发生在这一行：

 Instance = Me

异常信息：

类型 'System.TypeInitializationException' 的异常发生在 SampleApp.exe 但未在用户代码中处理

附加信息：'SampleApp.Views.Shell' 的类型初始值设定项引发异常。

InnerException: 对象引用未设置到对象的实例。

我怎样才能让这个 VB.NET class 工作？谢谢！

Answer 1

您对 'HamburgerMenu' 属性 的转换不正确。 使用：

Public Shared ReadOnly Property HamburgerMenu() As HamburgerMenu
    Get
        Return Instance.MyHamburgerMenu
    End Get
End Property

原始 C# 使用 'expression-bodied' 成员作为 'HamburgerMenu' - 此功能在 VB 中不可用。