Question

我有一个使用collectionsource的列表视图，并希望根据ListViewItems在列表中的索引是否与视图模型中保存的值相匹配来设置背景颜色。为此，我将listVeiwItem的背景绑定到ViewModel中的值，并使用转换器确定背景色。为了进行此确定，需要向转换器传递ListViewItem的索引。如何使用XAML获取索引？

这是ListView使用的数据模板的XAML：

<DataTemplate x:Key="ILMemberTemplate">
    <StackPanel Orientation="Horizontal" Background="{Binding Path=ListIndex, Mode=OneWay, Converter={StaticResource ParticipantBackground}, ConverterParameter={???}}">
        <TextBlock
            Width="200"
            TextAlignment="Left"
            Foreground="{Binding Path=IsPC, Mode=OneWay, Converter={StaticResource ParticipantColour}}"
            Text="{Binding Path=Name, Mode=OneWay}"/>
        <TextBlock
            Width="40"
            TextAlignment="Center"
            Foreground="{Binding Path=IsPC, Mode=OneWay, Converter={StaticResource ParticipantColour}}"
            Text="{Binding Path=Initiative, Mode=OneWay}"/>
    </StackPanel>
</DataTemplate>

Answer 1

您无法在XAML中获取索引并将其作为items: [{ title: 'Please select a date:', width: 330, bodyPadding: 10, items: [{ xtype: 'datepicker', disabledDays: [0,6], minDate: Ext.Date.add(new Date(), Ext.Date.DAY, -42), maxDate: Ext.Date.add(new Date(), Ext.Date.DAY, -7), listeners: { select: function (picker, date) { console.log(date); } }传递。这是不可能的。但是您可以使用多转换器并绑定到ConverterParameter和父ListIndex容器，例如：

ListViewItem

XAML：

class MultiConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        var listIndex = values[0];
        //...
        ListViewItem item = value as ListViewItem;
        ListView lv = FindParent<ListView>(item);
        ICollectionView view = lv.ItemsSource as ICollectionView;
        IEnumerator e = view.GetEnumerator();
        int index = 0;
        while (e.MoveNext())
        {
            if (Equals(item.DataContext, e.Current))
                return index;
            else
                index++;
        }

        //return some brush based on the indexes..
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotSupportedException();
    }

    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);
    }
}

如何获取ListViewItem的索引？

1 个答案: