如何根据列表项的绑定值更改其视觉样式？

Question

我有一个列表框（这是 xaml）：

            <ListBox MinWidth="300" ItemsSource="{Binding Relationships, Mode=OneWay}" 
        SelectedItem="{Binding SelectedRelationship, Mode=TwoWay}" SelectionMode="Single" 
        HorizontalAlignment="Left" >
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="Auto"/>
                            <ColumnDefinition/>
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions>
                            <RowDefinition/>
                            <RowDefinition/>
                            <RowDefinition/>
                            <RowDefinition/>
                            <RowDefinition/>
                            <RowDefinition/>
                        </Grid.RowDefinitions>
                        <CheckBox IsChecked = "{Binding IsPrimary}" IsHitTestVisible="False" />
                        <StackPanel Orientation="Horizontal" Grid.Column="1">
                            <TextBlock Text="{Binding RelationshipType}"  FontWeight="Bold"  Margin="0,0,5,0" />
                            <TextBlock Text="{Binding Status}"  FontStyle="Italic" />                           
                        </StackPanel>
                        <TextBlock Text="{Binding UnitName}" Grid.Row="1" Grid.Column="1" />
                        <TextBlock Text="{Binding StartDate, Converter={StaticResource DateConverter}}" Grid.Row="2" Grid.Column="1"/>
                        <TextBlock Text="{Binding RetireDate}" Grid.Row="3" Grid.Column="1" />
                        <TextBlock Text="{Binding EndDate}" Grid.Row="4" Grid.Column="1" />
                        <TextBlock Text="{Binding ReasonForLeaving}" Grid.Row="5" Grid.Column="1" />
                    </Grid>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

我想要做的是让列表框中的每个项目都有 3 个背景之一（如果 IsPrimary = true 则为绿色，如果 EndDate 值为空则为橙色，如果 EndDate 值为灰色）不为空。

没有办法对列表框项目进行模板化，以便它们评估绑定项目以确定视图状态或将每个列表框项目绑定到我可以为视图模型中的每个项目设置的值？

有

Answer 1

我认为您需要将项目网格的背景绑定到 DataContext 的值，并通过转换器传递它来实现您的逻辑。类似于

<Grid Background="{Binding Converter={StaticResource myItemConverter}}">
   ...
</Grid>

转换器的样子

public class MyItemConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var item = value as ItemModel; // [Your ListboxItem Class];
        if (item.IsPrimary)
            return System.Windows.Media.Brushes.Green;
        return item.EndDate.HasValue ? 
            System.Windows.Media.Brushes.Gray : 
            System.Windows.Media.Brushes.Orange;
    }
}