编辑属性后不刷新相关实体的转换值

Question

我正在VS2019中使用.net core 3.1。我有一个包含一个ListView的用户控件，该ListView列出了价格表的一组项目，每个项目都有一个名为Promotion的相关实体提供的Cost，Markup（百分比），折扣（％）和SalePrice，FinalPrice和PromoDescription由转换器计算的字段。例如，如果项目没有促销，FinalPrice等于SalePrice，否则为（SalePrice-SalePrice * item.Promotion.Discount / 100.0）。

顺便说一句，所有这些实体都属于EF核心模型，并带有代理的延迟加载，并且所有集合都是ObervableCollection，其加载方式如下：

var dbset = Context.Promos;
            dbset.Load();
            return dbset.Local.ToObservableCollection();

除我更改标记或促销属性外，其他所有操作均正常，这会导致重新计算转换器提供的值，并且不涉及或具有Promo类型的一个相关实体。 调试窗口，我可以看到在基础视图模型中正确应用的所有更改在将其确认到数据库之前和之后，但是我必须强制其刷新如下图所示的值。

这是窗口的最终组成：

窗口
- TabControl
  - TabItem（n）
    - PriceListUserControl（我的用户控件）

这里是模型：

这里是包含列表视图的用户控件的wpf：

<UserControl x:Class="MyApp.View.UserControls.PriceListUserControl"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         xmlns:local="clr-namespace:MyApp.View.UserControls"
         xmlns:localModel="clr-namespace:MyApp.Model"
         xmlns:localVm="clr-namespace:MyApp.ViewModel"
         mc:Ignorable="d" 
         d:DesignHeight="450" d:DesignWidth="800" 
         x:Name="UserControlPriceList">
<UserControl.Resources>
    <localVm:PriceListItemConverter x:Key="priceListItemConverter"/>
    <localVm:DateConverter x:Key="dateConverter"/>
    <localVm:PromoConverter x:Key="promoConverter" />

        <Border Style="{StaticResource BorderStyle}" Name="bottomBorder">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                    <RowDefinition />
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="106" />
                    <ColumnDefinition Width="*" />
                </Grid.ColumnDefinitions>

                <TextBlock Grid.Row="0" Grid.Column="0" Style="{StaticResource SmallTitleStyle}" Margin="5"> Producto:</TextBlock>
                <TextBlock Grid.Row="1" Grid.Column="0" Style="{StaticResource SmallTitleStyle}" Margin="5"> Costo:</TextBlock>
                <TextBlock Grid.Row="2" Grid.Column="0" Style="{StaticResource SmallTitleStyle}" Margin="5"> Markup (%):</TextBlock>
                <TextBlock Grid.Row="3" Grid.Column="0" Style="{StaticResource SmallTitleStyle}" Margin="5"> Precio de Lista:</TextBlock>
                <TextBlock Grid.Row="4" Grid.Column="0" Style="{StaticResource SmallTitleStyle}" Margin="5"> Promoción:</TextBlock>
                <TextBlock Grid.Row="5" Grid.Column="0" Style="{StaticResource SmallTitleStyle}" Margin="5"> Precio Final:</TextBlock>

                <TextBlock Name="ProductDescription" Grid.Row="0" Grid.Column="1" HorizontalAlignment="Left"
                         Text="{Binding Path=Product.Description}"
                         Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" />
                <TextBlock Name="CostPrice" Grid.Row="1" Grid.Column="1" HorizontalAlignment="Left"
                         Text="{Binding Path=Product.CostPrice, StringFormat=C}"
                         Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" />
                <TextBox Name="MarkupPriceEntryForm" AutomationProperties.Name="Markup" Grid.Row="2" Grid.Column="1" HorizontalAlignment="Left"
                            Validation.ErrorTemplate="{StaticResource ValidationTemplate}"
                         Style="{StaticResource TextStyleTextBox}" Margin="8,5,0,5" IsReadOnly="{Binding ElementName=UserControlPriceList, Path=DataContext.IsReadOnly}" >
                    <TextBox.Text>
                        <Binding Path="Markup" StringFormat="N2" UpdateSourceTrigger="PropertyChanged">
                            <Binding.ValidationRules>
                                <ExceptionValidationRule />
                            </Binding.ValidationRules>
                        </Binding>
                    </TextBox.Text>
                </TextBox>
                <TextBlock Name="SalePrice" Grid.Row="3" Grid.Column="1" HorizontalAlignment="Left"
                         Text="{Binding Converter={StaticResource priceListItemConverter}, ConverterParameter=SalePrice, StringFormat=C}"
                         Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" />
                <TextBlock Name="Promotion" Grid.Row="4" Grid.Column="1" HorizontalAlignment="Left" 
                       Text="{Binding Converter={StaticResource priceListItemConverter}, ConverterParameter=PromoFriendlyDescription}"
                         Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" 
                         Visibility="{Binding ElementName=UserControlPriceList, Path=DataContext.HideIfEditing}"/>
                <ComboBox Name="PromosComboBox" AutomationProperties.Name="PromoDiscount" Grid.Row="4" Grid.Column="1" HorizontalAlignment="Left"                             
                          Text="(Seleccione promo)"
                          ItemsSource="{Binding ElementName=UserControlPriceList, Path=DataContext.PromoCollection}"                              
                          SelectedValue="{Binding ElementName=UserControlPriceList, Path=DataContext.Current.PromoId, Mode=TwoWay}"
                          SelectedValuePath="Id"                               
                          Style="{StaticResource ComboBoxStyle}"
                          ItemContainerStyle="{StaticResource ComboBoxItemStyle}" Margin="8,5,0,5"
                          IsTextSearchEnabled="True"
                          IsTextSearchCaseSensitive="False"
                          IsDropDownOpen="False"
                          StaysOpenOnEdit="True"                              
                          IsEditable="True" IsReadOnly="False"
                          Visibility="{Binding ElementName=UserControlPriceList, Path=DataContext.ShowIfEditing}" 
                          Width="{Binding ElementName=Promotion, Path=Width}">
                    <ComboBox.Resources>
                        <DataTemplate DataType="{x:Type localModel:Promo}">
                            <TextBlock Text="{Binding Converter={StaticResource promoConverter}, ConverterParameter=PromoFriendlyDescription}"/>
                        </DataTemplate>
                    </ComboBox.Resources>                                               
                </ComboBox>                    
                <TextBlock Name="FinalPrice" Grid.Row="5" Grid.Column="1" HorizontalAlignment="Left"
                         Text="{Binding Converter={StaticResource priceListItemConverter}, ConverterParameter=FinalPrice, StringFormat=C}"
                         Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" />
            </Grid>
        </Border>
    </DataTemplate>
</UserControl.Resources>

<Border Padding="20">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <TextBlock Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2" Style="{StaticResource MediumTitleStyle}" Margin="5" 
                   Text="{Binding Path=List.Name, StringFormat='Lista: {0}'}" />
        <TextBlock Grid.Row="0" Grid.Column="2" Grid.ColumnSpan="2" Style="{StaticResource MediumTitleStyle}" Margin="5" HorizontalAlignment="Right"
                   Text="{Binding Path=List.PrintDate, StringFormat='Última impresión: {0:dd/MM/yyyy}'}" />

        <Border Grid.Row="1" Style="{StaticResource BorderStyle}" Grid.ColumnSpan="4">
            <ListView Name="ListViewPriceListItems" Grid.Row="1" Grid.ColumnSpan="4" 
                          ItemsSource="{Binding Path=Items}" 
                      IsSynchronizedWithCurrentItem="True"
                      SelectionChanged="OnPriceListItemSelectionChanged"
                      MouseDoubleClick="EnterPriceListItemEditMode"
                      IsEnabled="{Binding Path=IsReadOnly}">
                <ListView.View>
                    <GridView AllowsColumnReorder="true" ColumnHeaderToolTip="Detalle de productos, precios finales y promociones">
                        <GridViewColumn DisplayMemberBinding="{Binding Path=Product.Description}" Header="Producto" Width="300"/>
                        <GridViewColumn DisplayMemberBinding="{Binding Path=Product.CostPrice, StringFormat=C}" Header="Costo"/>
                        <GridViewColumn DisplayMemberBinding="{Binding Path=Markup, StringFormat=N2}" Header="Markup (%)" />
                        <GridViewColumn DisplayMemberBinding="{Binding Converter={StaticResource priceListItemConverter}, ConverterParameter=SalePrice, StringFormat=C}" Header="Precio Lista"/>
                        <GridViewColumn DisplayMemberBinding="{Binding Converter={StaticResource priceListItemConverter}, ConverterParameter=PromoFriendlyDescription}" Header="Promoción" Width="200" />
                        <GridViewColumn DisplayMemberBinding="{Binding Converter={StaticResource priceListItemConverter}, ConverterParameter=FinalPrice, StringFormat=C}" Header="Precio Final" />
                    </GridView>
                </ListView.View>
            </ListView>
        </Border>
        <ContentControl Name="PriceListDetail" Grid.Row="2" Grid.ColumnSpan="4"
                    Content="{Binding Path=Current}"
                    ContentTemplate="{StaticResource PriceListItemDetailTemplate}"
                    Margin="9,0,0,0" />

        <StackPanel Grid.Row="3" Grid.ColumnSpan="4" Orientation="Horizontal" HorizontalAlignment="Right">
            <StackPanel.Resources>
                <Style TargetType="{x:Type Button}">
                    <Setter Property="Margin" Value="0,0,0,0"/>
                </Style>
            </StackPanel.Resources>
            <Button Name="EditButton" HorizontalAlignment="Right" Content="_Modificar" Style="{StaticResource AcctionButtonStyle}" 
                        ToolTip="Editar precio y promoción del producto seleccionado en esta lista."
                        Click="EditSelectedPriceListItem" Visibility="{Binding Path=HideIfEditing}"/>
            <Button Name="SaveButton" HorizontalAlignment="Right" Content="_Aceptar" Style="{StaticResource ActionButtonOKStyle}" 
                        ToolTip="Guardar los cambios realizados."
                        Click="SavePriceListItem" Visibility="{Binding Path=ShowIfEditing}"/>
            <Button Name="CancelButton" HorizontalAlignment="Right" Content="_Cancelar" Style="{StaticResource ActionButtonCancelStyle}" 
                        ToolTip="Deshacer los cambios realizados."
                        Click="UndoPriceListItem" Visibility="{Binding Path=ShowIfEditing}"/>
        </StackPanel>
    </Grid>
</Border>

这是它的视图模型：

public partial class PriceListItemsViewModel: BaseViewModel<PriceListItem>
{
    private PriceList _list;

    public PriceListItemsViewModel(PriceList list, ObservableCollection<Promo> promoCollection)
    {

        this.List = list ?? throw new ArgumentNullException(nameof(list));
        this.PromoCollection = promoCollection;
        this.Items = list.Products;         
        this.IsEditMode = false;
        this.IsNew = false;
        this.Current = this.Items.FirstOrDefault();
    }

    public PriceList List { get => this._list; set => this._list = value; }
    public ObservableCollection<Promo> PromoCollection { get; }
}

注意：BaseViewModel具有ObservableCollection，实现Generic INotifyPropertyChange，并具有公共属性以指示该集合中当前选定的项目以及其他有用状态

这里是包含先前用户控件的视图的wpf：

<Window.Resources>                
    <uc:PriceListUserControl x:Key="userControlPList"/>
</Window.Resources>

<Border Padding="20">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>

        <TabControl x:Name="TabControlPriceLists" Grid.Row="1" Grid.ColumnSpan="3" TabStripPlacement="Top"
                    ItemsSource="{Binding Items}"
                    SelectedItem="{Binding Current}"
                    IsEnabled="{Binding IsReadOnly}" >
            <TabControl.Resources>
                <DataTemplate DataType="{x:Type localVm:PriceListItemsViewModel}">
                    <uc:PriceListUserControl x:Name="UserControlPriceList"/>
                </DataTemplate>
            </TabControl.Resources>
            <TabControl.ItemContainerStyle>
                <Style TargetType="TabItem">
                    <Setter Property="Header" Value="{Binding List.Name}" />
                    <Setter Property="MaxWidth" Value="100" />
                    <Setter Property="ToolTip" Value="{Binding List.Name}" />
                    <Setter Property="Background" Value="Bisque" />
                    <Setter Property="FontWeight" Value="DemiBold" />                        
                    <EventSetter Event="MouseDoubleClick" Handler="OnTabItemDoubleClick"/>
                </Style>                    
            </TabControl.ItemContainerStyle>
        </TabControl>

    </Grid>
</Border>

及其视图模型：

public class PriceListsViewModel : BaseViewModel<PriceListItemsViewModel>
{
    private ObservableCollection<Promo> promoCollection;
    public PriceListsViewModel()
    {
        var promoDefaultItems = new List<Promo>
        {
            new Promo { FriendlyName = PromoConverter.PromoFriendlyNameNoPromo, DiscountPct = 0.0F } //Workaround: Adds "(No promo) to allow the user to left an item without promotion
            //new Promo { FriendlyName = PromoConverter.PromoFriendlyNameNewPromo, DiscountPct = 0F }
        };
        this.promoCollection = new ObservableCollection<Promo>(promoDefaultItems);
        var promos = PromoRepository.PromoGetAll();
        foreach (var promo in promos)
        {
            this.promoCollection.Add(promo);
        }
        var lists = PriceListRepository.PriceListGetAll();
        this.Items = new ObservableCollection<PriceListItemsViewModel>();
        foreach (var l in lists)
        {
            this.Items.Add(new PriceListItemsViewModel(l, promoCollection));
        }
        this.IsEditMode = false;
        this.IsNew = false;
        this.Current = this.Items.FirstOrDefault();

    }
}

Answer 1

我通过创建一个新的视图模型来解决此问题，该视图模型包装了以前的PriceListItem并提供了真实的属性并通知其更改。这是新的视图模型（只有相关代码才能显示新属性）

public class PriceListItemViewModel : SupervisedEntity { private PriceListItem _item; public PriceListItemViewModel(PriceListItem item) { this._item = item ?? throw new ArgumentNullException(nameof(item)); //Bind the parent properties to its dependants (actually they are computed properties without setter) so they notify property changes when their parent property changes. this.AddDependentProperty(nameof(this.PromoId), nameof(this.SalePrice)); this.AddDependentProperty(nameof(this.PromoId), nameof(this.FinalPrice)); this.AddDependentProperty(nameof(this.PromoId), nameof(this.PromoFriendlyDescription)); this.AddDependentProperty(nameof(this.Markup), nameof(this.SalePrice)); this.AddDependentProperty(nameof(this.Markup), nameof(this.FinalPrice)); } // The properties and code not related to the solution were removed for clarity public int? PromoId { get => this._item.PromoId; set { this._item.PromoId = (value is null || value == 0) ? null : value; this.NotifyPropertyChanged(); //This notifies not only the change in PromoId but also in all its dependent properties } } public string ProductDescription => this._item.Product.Description; public float CostPrice => this._item.Product.CostPrice; [Required] public float Markup { get => this._item.Markup; set { this._item.Markup = value; this.NotifyPropertyChanged(); } } //Using properties instead of extension methods allows me to create notification for them as dependent public float SalePrice => this._item.SalePrice(); public float FinalPrice => this._item.FinalPrice(); public int Id => this.Item.Id; public string PromoFriendlyDescription => this._item.PromoId is null ? string.Empty : this._item.Promotion.ToString(); }

并且在用户控件的xaml中，我用新视图模型中的实际属性替换了所有转换器，当它们依赖的一个属性发生更改时，它们没有得到通知。首先，用新的视图模型替换模型的类，如下所示：

<DataTemplate x:Key="PriceListItemDetailTemplate" DataType="{x:Type localVm:PriceListItemViewModel}">

然后在更改的属性中替换对转换器的所有引用：<TextBlock Name="SalePrice" Grid.Row="3" Grid.Column="1" HorizontalAlignment="Left"
                     Text="{Binding Converter={StaticResource priceListItemConverter}, ConverterParameter=SalePrice, StringFormat=C}"
                     Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" />
<TextBlock Name="FinalPrice" Grid.Row="5" Grid.Column="1" HorizontalAlignment="Left"
                     Text="{Binding Converter={StaticResource priceListItemConverter}, ConverterParameter=FinalPrice, StringFormat=C}"
                     Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" />

通过新视图模型中的实际属性：<TextBlock Name="SalePrice" Grid.Row="3" Grid.Column="1" HorizontalAlignment="Left"
                         Text="{Binding Path=SalePrice, StringFormat=C}"
                         Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" />                      
<TextBlock Name="FinalPrice" Grid.Row="5" Grid.Column="1" HorizontalAlignment="Left"
                         Text="{Binding Path=FinalPrice, StringFormat=C}"
                         Style="{StaticResource TextStyleTextBlockTextBoxLike}" Margin="8,5,0,5" />

现在可以使用。

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编辑属性后不刷新相关实体的转换值

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