wpf - 多绑定(bind)时观察集合不更新

Question

我在 ViewModel 中有一个静态的 ObservableCollection MarketList 和它以下列方式绑定(bind)到 Table:

<FlowDocumentScrollViewer Height="216" VerticalAlignment="Top" Margin="-7,2,7,0" >
    <FlowDocument>
        <Table CellSpacing="0" Name="MBPTable"  >
            <Table.DataContext>
                <MultiBinding  UpdateSourceTrigger="Explicit"  Mode="TwoWay" Converter="{StaticResource indexerConverter}">
                    <Binding Path="MarketList" UpdateSourceTrigger="PropertyChanged" NotifyOnSourceUpdated="True" Mode="TwoWay" BindsDirectlyToSource="True"  />
                    <Binding Path="MBPindex"  Mode="TwoWay"   />
                </MultiBinding>
            </Table.DataContext>
        <Table.Resources>
            <local:IndexerConverter x:Key="indexerConverter"></local:IndexerConverter>
        </Table.Resources>

Table 包含绑定(bind)到 MarketList 属性的 ListView。

<ListView  Name="MarketByPriceList" Width="300" ItemsSource="{Binding MarketByPriceList, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" AlternationCount="2" Margin="0,15,0,0" >
    <ListView.View>
        <GridView>
            <GridViewColumn Header="Orders"  Width="48"  DisplayMemberBinding="{Binding MBP_NoofBuy_Orders, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" ></GridViewColumn>
            <GridViewColumn Header="Bid Qty" Width="48"  DisplayMemberBinding="{Binding MBPBID_Qty,  UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" ></GridViewColumn>
        </GridView>
    </ListView.View>
</ListView>

这是转换器方法

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (values != null && values[0] != DependencyProperty.UnsetValue)
        {
           // ObservableCollection<GlobalItems.Model.MarketWatchModel> allNames = (ObservableCollection<GlobalItems.Model.MarketWatchModel>)values[0];
            int index = (int)values[1];

            return GlobalItems.ViewModel.MarketWatchModelView.MarketList[index];
        }
        else
        {
            return null;
        }
    }

绑定(bind)工作正常，但集合中的更新未反射(reflect)在 UI 中

Answer 1

这似乎归结为描述的相同问题 here ，本质上是 same solution应该可以。

更新(添加或删除)ObservableCollection 不会导致您的 MultiBinding 刷新，因为 MultiBinding 正在监听 PropertyChanged 事件并且更新 ObservableCollection 只会触发 CollectionChanged 事件。一个干净的解决方法是将 Binding 添加到 MultiBinding 中 ObservableCollection 的 Count 属性。例如

<MultiBinding  UpdateSourceTrigger="Explicit"  Mode="TwoWay" Converter="{StaticResource indexerConverter}">
  <Binding Path="MarketList" UpdateSourceTrigger="PropertyChanged" NotifyOnSourceUpdated="True" Mode="TwoWay" BindsDirectlyToSource="True"  />
  <Binding Path="MBPindex"  Mode="TwoWay"   />
  <Binding Path="MarketList.Count" /> <!-- Additional Binding causes refresh when MarketList is updated -->
</MultiBinding>

在所有现有绑定(bind)之后添加附加绑定(bind)，以便 MultiValueConverter 可以忽略额外的值。当您的 ObservableCollection 的 Count 属性更改时(当您添加或删除项目时)，它将触发 PropertyChanged 事件并且您的 MultiBinding 将刷新。