Observable Collection 不更新 UI

Question

我正在研究在可观察集合中添加和删除行的能力。我有 UserControl 视图，ListView 绑定到 ObservableCollection。我还删除了在 ViewModel 中运行的命令，但不更新 UI.

这是我在 ViewModel 上的代码，继承自 MvvmLight ViewModelBase class。

 public class ProductInfoViewModel : ViewModelBase
{
    #region Properties

    private ObservableCollection<Product> _productList;
    public ObservableCollection<Product> ProductList
    {
        get { return _productList; }
        set
        {
            _productList =  value;
            RaisePropertyChanged("ProductList");
        }
    }

    #endregion
    #region Constructor
    public ProductInfoViewModel()
    {
        ConnectWebService connect = new ConnectWebService();
        string json = connect.getResponse(@"http://localhost:8082/products");
        ProductList = JsonConvert.DeserializeObject<ObservableCollection<Product>>(json);
        DeleteCommand = new RelayCommand<long>((id) => DeleteCommandHandler(id, ProductList));
    }
    #endregion
    #region Commands
    public ICommand DeleteCommand { get; private set; }
    #endregion
    #region CommandsHandlers
    private void DeleteCommandHandler(long id, ObservableCollection<Product> productList)
    {
        try
        {
            productList.Remove(productList.Where(i => i.ProductId == id).First());

        }
        catch (Exception)
        {
        }
    }

这是我在 XAML 中的代码：

<UserControl.DataContext>
    <local:ProductInfoViewModel/>
</UserControl.DataContext>
<Grid>
    <Grid Margin="0,50,0,100">
        <ListView  Margin="5" SelectionChanged="ListView_SelectionChanged" ItemsSource="{Binding ProductList, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Foreground="Black" Background="White" BorderBrush="{x:Null}" 
                   x:Name="ProductList">
            <ListView.View>
                <GridView>
                    <GridViewColumn  Header="Kod" Width="50" DisplayMemberBinding="{Binding ProductCode}"/>
                    <GridViewColumn  Header="Nazwa" Width="150" DisplayMemberBinding="{Binding ProductName}" />
                    <GridViewColumn  Header="Typ" Width="150" DisplayMemberBinding="{Binding ProductType}" />
                    <GridViewColumn  Header="Opis" Width="300" DisplayMemberBinding="{Binding ProductDescription}" />
                    <GridViewColumn  Header="Dostępność" Width="150" DisplayMemberBinding="{Binding ProductAvability}" />
                    <GridViewColumn Width="80">
                        <GridViewColumn.CellTemplate>
                            <DataTemplate>
                                <Button Content="Edytuj" Background="Transparent" BorderThickness="0" Foreground="Blue" Width="50" Margin="0" HorizontalAlignment="Center"
                                        Click="Button_Click"/>
                            </DataTemplate>
                        </GridViewColumn.CellTemplate>
                    </GridViewColumn>
                    <GridViewColumn Width="80">
                        <GridViewColumn.CellTemplate>
                            <DataTemplate>
                                <Button Content="Usuń" Background="Transparent" BorderThickness="0" Foreground="Blue" Width="50" Margin="0" HorizontalAlignment="Center" 
                                        Click="Delete_Click" Command="{Binding ProductInfoView.DeleteCommand, Mode=OneWay, Source={StaticResource Locator}}" CommandParameter="{Binding ProductId}"
                                         />
                            </DataTemplate>
                        </GridViewColumn.CellTemplate>
                    </GridViewColumn>
                </GridView>
            </ListView.View>
        </ListView>
    </Grid>

我的产品class实现了INotifyPropertyChanged接口，但我也用Fody

现在，只有当我将一个视图更改为另一个视图然后返回时，视图才会更新。我不知道出了什么问题。如有任何帮助，我将不胜感激！

Answer 1

当您从列表中删除项目时，您不会使用您的产品列表 setter，因此 RaisePropertyChanged 不会被调用。一个快速的解决方法是在删除项目后添加对 RaisePropertyChanged 的调用：

productList.Remove(productList.Where(i => i.ProductId == id).First());
RaisePropertyChanged("ProductList");

Answer 2

您正在将 Button 的 Command 属性绑定到 Locator 资源返回的视图模型。您应该将它绑定到 ListView 绑定到的同一实例：

<DataTemplate>
    <Button Content="Usuń" Background="Transparent" BorderThickness="0" Foreground="Blue" Width="50" Margin="0" HorizontalAlignment="Center" 
            Click="Delete_Click"
            Command="{Binding DataContext.DeleteCommand, RelativeSource={RelativeSource AncestorType=ListView}}" 
            CommandParameter="{Binding ProductId}"/>
</DataTemplate>

Observable Collection 不更新 UI

Observable Collection do not update the UI

wpf

listview

observablecollection

mvvm

mvvm-light