在LoadAsync（查询）完成从服务器加载数据之前调用的LoadCompleted（）方法。 LoadCompleted（）中出现空数据内部异常？

Question

    public MainPage()
    {
        try
        {
            InitializeComponent();
            Loaded += new RoutedEventHandler(MainPage_Loaded);
        }
        catch (Exception exc)
        {
            MessageBox.Show(exc.Message.ToString());
        }
    }

为RoutedEventHandler创建处理程序的构造函数。

    void MainPage_Loaded(object sender, RoutedEventArgs e)
    {
        listdata_uri = new Uri(Thr_Uri,UriKind.RelativeOrAbsolute);           
        context = new THRDataContext(listdata_uri);
        context.Credentials = new NetworkCredential(Username, Password, Thr_Uri);
        NewProjectData = new DataServiceCollection<NewProjectItem>(context);
        DataServiceQuery<NewProjectItem> query = context.NewProject;
        NewProjectData.LoadCompleted += new EventHandler<LoadCompletedEventArgs>(NewProjectData_LoadCompleted);
        NewProjectData.LoadAsync(query);            
    }

这里我创建了LoadCompleted事件并调用了loadasync方法。

    void NewProjectData_LoadCompleted(object sender, LoadCompletedEventArgs e)
    {            
        if (e.Error == null)
        {
            if (NewProjectData.Continuation != null)
            {
                NewProjectData.LoadNextPartialSetAsync();
            }
            else
            {
                this.DataContext = NewProjectData;
            }
        }
        string error = e.Error.ToString();
        MessageBox.Show(error);            
    }   

此处msg框显示LoadCompletedEventArgs e获取null时生成的错误。