WPF ListView更改ComboBox單元格項目焦點上的選定項目或更改

Question

對於ListView，行中有多個組合框。 我還具有綁定到所選行的文本框，以顯示ListView下一行的其他信息。 問題在於，當您單擊一行中的ComboBox時，該行的ListView所選項目/索引不會更改。 選擇該行中的ComboBox時，如何更改該行在ListView中的所選項目？

這是我的ComboBox ListView：

<ListView Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="4" VerticalAlignment="Stretch" 
        ItemsSource="{Binding Equations.DataExpressions}" SelectedItem="{Binding Equations.SelectedExpression}" SelectedIndex="0">
<ListView.Resources>
    <Style TargetType="{x:Type ListViewItem}">
        <Setter Property="HorizontalContentAlignment" Value="Stretch" />
        <Setter Property="VerticalContentAlignment" Value="Stretch" />
        <Style.Triggers>
            <DataTrigger Binding="{Binding IsValidExpression}" Value="false">
                <Setter Property="Background" Value="#FF8080" />
            </DataTrigger>
        </Style.Triggers>
    </Style>
</ListView.Resources>
<ListView.View>
    <GridView>
        <GridViewColumn Header="Path" Width="90">
            <GridViewColumn.CellTemplate>
                <DataTemplate>
                    <ComboBox ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.PathItems}" 
                                SelectedValue="{Binding EvaluatedPath}" Margin="-6, 0, -6, 0" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                    </ComboBox>
                </DataTemplate>
            </GridViewColumn.CellTemplate>
        </GridViewColumn>
    </GridView>
</ListView.View>

Answer 1

將事件處理程序添加到您的Style並處理PreviewMouseLeftButtonDown事件：

private void lv_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    ListViewItem lvi = (ListViewItem)sender;
    ListView lv = FindParent<ListView>(lvi);
    lv.SelectedItem = lvi.DataContext;
}

private static T FindParent<T>(DependencyObject dependencyObject) where T : DependencyObject
{
    var parent = VisualTreeHelper.GetParent(dependencyObject);

    if (parent == null) return null;

    var parentT = parent as T;
    return parentT ?? FindParent<T>(parent);
}

XAML：

<Style TargetType="{x:Type ListViewItem}">
    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
    <Setter Property="VerticalContentAlignment" Value="Stretch" />
    <EventSetter Event="PreviewMouseLeftButtonDown" Handler="lv_PreviewMouseLeftButtonDown" />
    <Style.Triggers>
        <DataTrigger Binding="{Binding IsValidExpression}" Value="false">
            <Setter Property="Background" Value="#FF8080" />
        </DataTrigger>
    </Style.Triggers>
</Style>

請注意，由於這純粹是與視圖/控件相關的邏輯，因此應在視圖中（代碼背后）實現。 視圖模型不負責控件的行為，因此不會破壞MVVM模式。