WPF MultiBinding 到后台属性不起作用

Question

MultiBinding 到背景属性不起作用。转换后，背景只是变成系统的默认颜色，而不是我在 MultiValueConverter 中设置的颜色。其他一切都已正确设置。我的 MultiBinding 到背景有什么问题？

<Style.Triggers>
    <DataTrigger Binding="{Binding Source={StaticResource triggerResource},
                                   Path=MyIsSelected}"         
                 Value="True">
        <Setter Property="Background">
            <Setter.Value>
                <MultiBinding Converter="{StaticResource groupNameToBackgroundConv}">
                    <Binding Path="Name" />
                    <Binding Source="{StaticResource selectedGroupName}" Path="Name" />
                </MultiBinding>
            </Setter.Value>
        </Setter>
    </DataTrigger>
</Style.Triggers>

我的 MultiValueConverter 是

 public class GroupNameToBackgroundConv : IMultiValueConverter
{
    private const string DEFAULT_COLOR = "#B8CBE9";
    private const string SELECTED_COLOR = "#FFFF00";       

    public object Convert(object[] values, Type targetType, object parameter,
        System.Globalization.CultureInfo culture)
    {
        string groupName = values[0] as string;
        string selectedGroupName = values[1] as string;

        if (groupName == null)
            return DEFAULT_COLOR;

        if (selectedGroupName == null)
            return DEFAULT_COLOR;

        if (groupName == selectedGroupName)
        {
            return SELECTED_COLOR;
        }
        else
        {
            return DEFAULT_COLOR;
        }


    }  // ends method

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter,
        System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }

} // ends class

Answer 1

我解决了这个问题。
Convert返回值时，需要为Brush，而不是string或Color
控件扩展器的背景属性。
这是我的转换器。

 public class GroupNameToBackgroundConv : IMultiValueConverter
{

    private Color DEFAULT_COLOR = (Color)ColorConverter.ConvertFromString("#B8CBE9");
    private Color SELECTED_COLOR = (Color)ColorConverter.ConvertFromString("#FFFF00");       

    public object Convert(object[] values, Type targetType, object parameter,
        System.Globalization.CultureInfo culture)
    {
        string groupName = values[0] as string;
        string selectedGroupName = values[1] as string;          

        if (groupName == null)
            return ColorOrBrush(DEFAULT_COLOR, targetType);

        if (selectedGroupName == null)
            return ColorOrBrush(DEFAULT_COLOR, targetType);

        if (groupName == selectedGroupName)
        {
            return ColorOrBrush(SELECTED_COLOR, targetType);
        }
        else
        {
            return ColorOrBrush(DEFAULT_COLOR, targetType);
        }



    }  // ends method


    private object ColorOrBrush(Color c, Type targetType)
    {
        if (targetType == typeof(Color))
            return c;
        else if (targetType == typeof(Brush))
            return new SolidColorBrush(c);
        else 
            return null;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter,
        System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }

} // ends class