服務正在返回空wpf mvvm

Question

我試圖綁定我的數據上下文中的數據，但服務返回null。我正在使用ninject作爲DI。我分享我的app.xaml.cs代碼。請指導我。

public partial class App 
{ 
    private IKernel container; 

    protected override void OnStartup(StartupEventArgs e) 
    { 
     base.OnStartup(e); 
     AutoMapperConfig.RegisterMappings(); 
     ConfigureContainer(); 
     ComposeObjects(); 
     Current.MainWindow.Show(); 
    } 

    private void ConfigureContainer() 
    { 
     this.container = new StandardKernel(); 
     container.Bind(typeof(IAppServiceBase<>)).To(typeof(AppServiceBase<>)); 
     container.Bind<IJvDetailAppService>().To<JvDetailAppService>().InSingletonScope(); 
     container.Bind<IJvMasterAppService>().To<JvMasterAppService>().InSingletonScope(); 
     container.Bind<IJvDimensionAppService>().To<JvDimensionAppService>().InSingletonScope(); 
     container.Bind(typeof(IServiceBase<>)).To(typeof(ServiceBase<>)); 
     container.Bind<IJvDetailService>().To<JvDetailService>(); 
     container.Bind<IJvMasterService>().To<JvMasterService>(); 
     container.Bind<IJvDimensionService>().To<JvDimensionService>(); 

     container.Bind(typeof(IRepositoryBase<>)).To(typeof(RepositoryBase<>)); 
     container.Bind<IJvDetailRepository>().To<JvDetailRepository>(); 
     container.Bind<IJvMasterRepository>().To<JvMasterRepository>(); 
     container.Bind<IJvDimensionRepository>().To<JvDimensionRepository>(); 
    } 

    private void ComposeObjects() 
    {   
     Current.MainWindow = this.container.Get<MainWindow>(); 
     Current.MainWindow.Title = "JustApp"; 
    } 
} 

MainWindowViewModel

public class MainWindowViewModel : ViewModelBase 
{ 
    private readonly BackgroundWorker _worker = new BackgroundWorker(); 

    private ObservableCollection<JvDetailViewModelBase> _jvDetailMenu; 
    private readonly IJvDetailAppService _jvDetailAppService; 

    public ObservableCollection<JvDetailViewModelBase> JvDetailMenu 
    { 
     get { return this._jvDetailMenu; } 
     set 
     { 
      _jvDetailMenu = value; 
      RaisedPropertyChanged("JvDetailMenu"); 
     } 
    } 

    public MainWindowViewModel() 
    { 
     _worker.DoWork += worker_DoWork; 
     _worker.RunWorkerCompleted += worker_RunWorkerCompleted; 
     _worker.RunWorkerAsync(); 

    } 

    readonly ObservableCollection<JvDetailViewModelBase> _tempProductMenu = new ObservableCollection<JvDetailViewModelBase>(); 
    private void worker_DoWork(object sender, DoWorkEventArgs e) 
    { 
     _tempProductMenu.Add(new ModifyJvDetailViewModel(_jvDetailAppService)); 
    } 

    private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) 
    { 
     if (_tempProductMenu.Any()) 
     { 
      JvDetailMenu = _tempProductMenu; 
     } 
    } 
} 

ModifyJvDetailViewModel.cs

public class ModifyJvDetailViewModel : JvDetailViewModelBase 
{ 
    private readonly BackgroundWorker _worker = new BackgroundWorker(); 

    private IEnumerable<JvDetail> _tempLoadJvDetails; 

    private readonly IJvDetailAppService _jvDetailAppService; 

    private void worker_DoWork(object sender, DoWorkEventArgs e) 
    { 
     int ab = _jvDetailAppService.GetByCompanyId(3).Count(); // it is returning null here and everywhere which is fetching records. 
     _tempLoadJvDetails = _jvDetailAppService.GetByCompanyId(3); 
    } 
    private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) 
    { 
     JvDetails = _tempLoadJvDetails; 
    } 
    public override string Name 
    { 
     get { return JustAppHelper.JvDetail; } 
    } 

    public override string Icon 
    { 
     get { return JustAppHelper.JvDetailIcon; } 
    } 


    public ModifyJvDetailViewModel(IJvDetailAppService jvDetailAppService) 
    { 
     _jvDetailAppService = jvDetailAppService; 
     var ab = _jvDetailAppService.GetAll().Count(); 

     _worker.DoWork += worker_DoWork; 
     _worker.RunWorkerCompleted += worker_RunWorkerCompleted; 
     _worker.RunWorkerAsync(); 
     BindGrid(); 

    } 

    protected void BindGrid() 
    { 
     JvDetails = _jvDetailAppService.GetByCompanyId(3); 
    } 

    private IEnumerable<JvDetail> _jvDetails; 
    public IEnumerable<JvDetail> JvDetails 
    { 
     get { return _jvDetails; } 
     set 
     { 
      _jvDetails = value; 
      RaisedPropertyChanged("JvDetails"); 
     } 
    } 
} 

Mainwindow.cs

public partial class MainWindow : Window 
    { 
     public MainWindow() 
     { 
      InitializeComponent(); 
      this.DataContext = new MainWindowViewModel(); 
      ListBoxProducts.SelectedIndex = 0; 
     } 
    } 

Answer 1

一種方法是改變MainWindowViewModel構造：

public MainWindowViewModel(IJvDetailAppService detailAppService) 
{ 
    _jvDetailAppService = detailAppService; 

    _worker.DoWork += worker_DoWork; 
    _worker.RunWorkerCompleted += worker_RunWorkerCompleted; 
    _worker.RunWorkerAsync(); 
} 

和MainWindow構造：

public MainWindow(IJvDetailAppService detailAppService) 
{ 
    InitializeComponent(); 
    this.DataContext = new MainWindowViewModel(detailAppService); 
    ListBoxProducts.SelectedIndex = 0; 
}