WPF DataContext does not update DataGrid using MVVM model

Question

Project Overview

I have a view that binds to a viewmodel containing 2 ObserverableCollection. The viewmodel constructor populates the first ObserverableCollection, and the view data file is assembled to bind to it through a public property called sites.

Later, a 2ed ObserverableCollection is entered into the LoadOrders method, and the public LoadFraudResults property is updated to bind it to the datacontext.

I use WCF to pull data from a database and get it very well.

SOURCE OF THE IMAGE

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();
    }

}

---

BROWSE SOURCE

public partial class 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"

DataGridSource = { = LoadFraudResults}

:

LoadOrderQueueForm , BindItemsSource 2ed , .

, BindItemsSource, obseravablecollection cmbWebsite_SelectionChanged, observalblecollection , LoadFraudResults viewmodule ; datacontext datagrid, datagrid .

, datagrid , datacontext 2ed BindItemsSource.

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

manageFraudOrderViewModel , datagrid .

, , ​​ 2 , .

Answer 1

datagrid.Items.Refresh()!

Answer 2

, ilu2009 .

MVVM modal DataGrid DataGrid.ItemsSource DataGrid.ItemsSource.Refresh() .