WPF DataContext不使用MVVM模型刷新DataGrid

Question

项目概述

我有一个 View ，它绑定(bind)到包含 2 个 ObserverableCollection 的 View 模型。 View 模型构造函数填充第一个 ObserverableCollection，并收集 View 数据上下文以通过名为 Sites 的公共(public)属性绑定(bind)到它。

稍后，2ed ObserverableCollection 会填充到 LoadOrders 方法中，并且更新公共(public)属性 LoadFraudResults 以将其与数据上下文绑定(bind)。

我正在使用 WCF 从数据库中提取数据，并且提取效果非常好。

查看模型源

class ManageFraudOrderViewModel:ViewModelBase 
{
    #region Fields        
    private readonly ICollectionView collectionViewSites;
private readonly ICollectionView collectionView;
    private ObservableCollection<GeneralAdminService.Website> _sites;
    private ObservableCollection<FraudService.OrderQueue> _LoadFraudResults;

    #endregion 

    #region Properties
    public ObservableCollection<GeneralAdminService.Website> Sites 
    {
        get { return this._sites; }
    }
    public ObservableCollection<FraudService.OrderQueue> LoadFraudResults 
    {
        get { return this._LoadFraudResults;}
    }
    #endregion

    public ManageFraudOrderViewModel()
    {
        //Get values from wfc service model
        GeneralAdminService.GeneralAdminServiceClient generalAdminServiceClient = new GeneralAdminServiceClient();
        GeneralAdminService.Website[] websites = generalAdminServiceClient.GetWebsites();
        //Get values from wfc service model            

        if (websites.Length > 0)
        {
            _sites = new ObservableCollection<Wqn.Administration.UI.GeneralAdminService.Website>();
            foreach (GeneralAdminService.Website website in websites)
            {
                _sites.Add((Wqn.Administration.UI.GeneralAdminService.Website)website);
            }

    this.collectionViewSites= CollectionViewSource.GetDefaultView(this._sites);
        }
        generalAdminServiceClient.Close();
    }

    public void LoadOrders(Wqn.Administration.UI.FraudService.Website website)
    {
        //Get values from wfc service model            
        FraudServiceClient fraudServiceClient = new FraudServiceClient();
        FraudService.OrderQueue[] OrderQueue = fraudServiceClient.GetFraudOrders(website);
        //Get values from wfc service model            

        if (OrderQueue.Length > 0)
        {
            _LoadFraudResults = new ObservableCollection<Wqn.Administration.UI.FraudService.OrderQueue>();
            foreach (FraudService.OrderQueue orderQueue in OrderQueue)
            {
                _LoadFraudResults.Add(orderQueue);
            }
        }

    this.collectionViewSites= CollectionViewSource.GetDefaultView(this._LoadFraudResults);
        fraudServiceClient.Close();
    }

}

<小时/>

查看源码

公共(public)分部类 OrderQueueControl : UserControl{

    private ManageFraudOrderViewModel manageFraudOrderViewModel ;
    private OrderQueue orderQueue;
    private ButtonAction ButtonAction;
    private DispatcherTimer dispatcherTimer;

    public OrderQueueControl()
    {

            LoadOrderQueueForm();
    }

    #region LoadOrderQueueForm
    private void LoadOrderQueueForm()
    {    
    //for binding the first observablecollection
        manageFraudOrderViewModel = new ManageFraudOrderViewModel();
        this.DataContext = manageFraudOrderViewModel;          
    }
    #endregion

    private void cmbWebsite_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        BindItemsSource();
    }

    #region BindItemsSource
    private void BindItemsSource()
    {
        using (OverrideCursor cursor = new OverrideCursor(Cursors.Wait))
        {

            if (!string.IsNullOrEmpty(Convert.ToString(cmbWebsite.SelectedItem)))
            {
                    Wqn.Administration.UI.FraudService.Website website = (Wqn.Administration.UI.FraudService.Website)Enum.Parse(typeof(Wqn.Administration.UI.FraudService.Website),cmbWebsite.SelectedItem.ToString());

        //for binding the second observablecollection*******
                    manageFraudOrderViewModel.LoadOrders(website);
                    this.DataContext = manageFraudOrderViewModel;
        //for binding the second observablecollection*******
            }            
        }
    }
    #endregion   

}

XAML

 ComboBox x:Name="cmbWebsite" ItemsSource="{Binding Sites}"  Margin="5" 
 Width="100" Height="25" SelectionChanged="cmbWebsite_SelectionChanged"
 DataGrid ItemsSource ={Binding Path = LoadFraudResults}

问题区域:

当我调用 LoadOrderQueueForm 绑定(bind)第一个 observablecollection 并随后调用 BindItemsSource 绑定(bind) 2ed observable 集合时，一切正常，第一次绑定(bind)没有问题。

但是，当我再次调用 BindItemsSource 以通过 cmbWebsite_SelectionChanged 根据更改的选定组合值重新填充 obseravablecollection 时，observalblecollection 会填充新值，并且 viewmodule 中的 LoadFraudResults 属性会填充新值；但是当我调用 datacontext 重新绑定(bind)数据网格时，数据网格没有反射(reflect)更改后的值。

换句话说，当在 View 的 BindItemsSource 方法中调用数据上下文 2 次时，数据网格不会发生更改。

 manageFraudOrderViewModel.LoadOrders(website);                    
 this.DataContext = manageFraudOrderViewModel;

manageFraudOrderViewModel 值正确，但数据网格未反射(reflect)更改的值。

请帮忙，因为过去两天我一直在处理这件事，而且截止日期即将来临。

提前致谢

Answer 1

尝试使用datagrid.Items.Refresh()!