WPF到后台属性的多重绑定不起作用

Question

MultiBinding to Background属性不起作用。当它被转换时，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。其他一切都设置得很好。我的多重绑定到后台有什么问题？

<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。当Convert返回一个值时，它需要是Brush，而不是字符串或Color控件扩展器的后台属性。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