c# - 为什么列表框项目在过滤期间不更新？

Question

我正在编写一个程序来查看列表框中的产品信息。我有一个用于搜索的文本框，它会在您按 ProductName 键入时自动过滤列表。我已经多次运行我的 C# 代码，我可以看到过滤器实际工作，但我无法直观地让它在屏幕上过滤或“刷新”。

C#代码：

private ICollectionView _ProductInfoView;
    public ICollectionView ProductInfoView 
    {
        get{return this._ProductInfoView;}
        set
        {
            this._ProductInfoView=value;
            this.onPropertyChnage("ProductInfoView");
        }
    }

 private void RibbonSetupProduct_Click(object sender, System.Windows.RoutedEventArgs e)
    {
        this.hidePanels();
        new Task(() =>
        {
            this.Dispatcher.Invoke(new Action(() =>
            {
                ObservableCollection<ModelProductInformation> productInfoCollection   = new ObservableCollection<ModelProductInformation>(from ProductInfo in new GTS_ERPEntities().ProductInformations select new ModelProductInformation { ProductID = ProductInfo.ProductID,  ProductName = ProductInfo.ProductName , Remark=ProductInfo.Remark});
                this.ProductInfoView = CollectionViewSource.GetDefaultView(productInfoCollection);
                new ProductInfoSearch(ProductInfoView, this.TestTextBox);
            }
                ), DispatcherPriority.DataBind);
        }
        ).Start(); 

        this.PanelProducts.Visibility = Visibility.Visible;
    }

  class ProductInfoSearch
   {
      public ProductInfoSearch(ICollectionView filteredList, TextBox textEdit)
      {
        string filterText = string.Empty;

        filteredList.Filter = delegate(object obj)
        {
            if (String.IsNullOrEmpty(filterText))
            {
                return true;
            }
            ModelProductInformation str = obj as ModelProductInformation;
            if (str.ProductName==null)
            {
                return true;
            }
            if (str.ProductName.ToUpper().Contains(filterText.ToUpper()))
            {
                return true;
            }
            else
            {
                return false;
            }
        };
        textEdit.TextChanged += delegate
        {
            filterText = textEdit.Text;
            filteredList.Refresh();
        };
    }
}

XAML：

<dxe:ListBoxEdit x:Name="ProductInfoList" Margin="1.666,1,8,8" Grid.Column="2" Grid.Row="2" Grid.RowSpan="5"  DisplayMember="ProductName" DataContext="{Binding ProductInfoView, ElementName=window}" ItemsSource="{Binding}"/>

我想我的问题要么是数据绑定，要么是在 Task() 内部。

Answer 1

我会将 ObservableCollection 设为私有字段，只需创建一次实例，也只需创建一次 ICollectionView。要添加新数据，您可以使用 clear 并添加到您的收藏中 - 试试吧，它对我有用。

 private ObservableCollection<ModelProductInformation> productInfoCollection;

 //ctor, just once in the constructor
 this.productInfoCollection =  new ObservableCollection<ModelProductInformation>();
 this.ProductInfoView = CollectionViewSource.GetDefaultView(productInfoCollection);
 new ProductInfoSearch(ProductInfoView, this.TestTextBox);


private void RibbonSetupProduct_Click(object sender, System.Windows.RoutedEventArgs e)
{
    this.hidePanels();
    new Task(() =>
    {
        this.Dispatcher.Invoke(new Action(() =>
        {
            var yourData = from ProductInfo in new GTS_ERPEntities().ProductInformations select new ModelProductInformation { ProductID = ProductInfo.ProductID,  ProductName = ProductInfo.ProductName , Remark=ProductInfo.Remark};
            //if you wanna change the collection, simple clear and add(or create AddRange extension)
           this.productInfoCollection.Clear();

           foreach(var data in yourData)
           { this.productInfoCollection.Add(data);}
        }
            ), DispatcherPriority.DataBind);
    }
    ).Start(); 

    this.PanelProducts.Visibility = Visibility.Visible;
}