WPF：在ListView的ObservableCollection外部进行绑定

Question

In WPF, I've got a ListView who's ItemSource is bound to an ObservableCollection:

<ListView ItemsSource="{Binding Path=TestList, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}">

TestList is a collection of type TestCase, which has several members. This works great for populating the ListView columns with info from the TestList members, but I also need to access properties from outside the collection.

There's a ComboBox (outside the ListView) that changes what controls are shown in certain columns. I tried to do this with setting a DataTrigger on the Visibility property:

<GridViewColumn Header="Area" Width="100">
    <GridViewColumn.CellTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Path=Area}">
                <TextBlock.Style>
                    <Style TargetType="{x:Type TextBlock}">
                        <Style.Setters>
                            <Setter Property="Visibility" Value="Visible"/>
                        </Style.Setters>
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding Path=IdentitySelection}" Value="Test Management">
                                <Setter Property="Visibility" Value="Collapsed"/>
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </TextBlock.Style>
            </TextBlock>
        </DataTemplate>
    </GridViewColumn.CellTemplate>
</GridViewColumn>

I've also got a few other spots where I need bindings from outside TestList (such as populating ComboBoxes within CellTemplates). However, the ListView doesn't seem to be getting data from anything outside the ItemSource.

I tried moving TestList and IdentitySelection into one class (TestManager), declaring that as one, large property, and binding to that:

<ListView ItemsSource="{Binding Path=TestManager, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}">
    <ListView.View>
        <GridView>
            <GridViewColumn Header="Area" Width="100">
                <GridViewColumn.CellTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding Path=TestList.Area}">
                            <TextBlock.Style>
                                <Style TargetType="{x:Type TextBlock}">
                                    <Style.Setters>
                                        <Setter Property="Visibility" Value="Visible"/>
                                    </Style.Setters>
                                    <Style.Triggers>
                                        <DataTrigger Binding="{Binding Path=IdentitySelection}" Value="Test Management">
                                            <Setter Property="Visibility" Value="Collapsed"/>
                                        </DataTrigger>
                                    </Style.Triggers>
                                </Style>
                            </TextBlock.Style>
                        </TextBlock>
                    </DataTemplate>
                </GridViewColumn.CellTemplate>
            </GridViewColumn>
        </GridView>
    </ListView.View>
</ListView>

That also did not work. Is there something I need to change about data context? I feel like there must be a way to do this. Any ideas are greatly appreciated.

Answer 1

Once you are in the DataTemplate , the DataContext switches to the bound item. No getting around it.

However , there are other bindings you can do. For example, if you need something off the main data context, you can do:

"{Binding ElementName=Root, Path=DataContext.MyProperty}"

Note your window or root element needs x:Name="Root" for that to work. You can also still get to resources via StaticResource bindings.