双向绑定，源不更新，使用两个转换器和两种类型的绑定，

Question

运行时会访问两个转换器，但访问第二个转换器Convert（）以将值变为红色，但永远不会访问Convert Back来禁用menuItem

 <Style>
   <Style.Triggers>
    <DataTrigger Value="True">
      <DataTrigger.Binding>
       <MultiBinding  Converter="{StaticResource MultiValueConverterColour}" >
          <Binding ElementName="upperLimitDefault" Path="Text" />
          <Binding ElementName="upperLimitMaximum"  Path="Text" />
          <Binding ElementName="upperLimitMinimum"  Path="Text" />
       </MultiBinding>
    </DataTrigger.Binding>
    <Setter Property="TextBox.Foreground"  Value="{Binding ElementName=menuItem, Path=IsEnabled, Mode=TwoWay, Converter={StaticResource myColorErrorConverter}, UpdateSourceTrigger=PropertyChanged}" />               
    </DataTrigger>
 </Style.Triggers>
              </Style>

两个转换器：

MultiValue：

 public class MultiValueConverterErrorColour : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        if (null != values)
        {

            string y = (String)values[0];
            string y2 = (String)values[1];
            string y3 = (String)values[2];

            if (string.IsNullOrEmpty(y) || string.IsNullOrEmpty(y2) || string.IsNullOrEmpty(y3))
                { return false; }
                var value = int.Parse(y, System.Globalization.NumberStyles.Integer);
                var value2 = int.Parse(y2, System.Globalization.NumberStyles.Integer);
                var value3 = int.Parse(y3, System.Globalization.NumberStyles.Integer);
                // int limit2 = int.Parse(limit, System.Globalization.NumberStyles.Integer);
                if (value >= value3 && value2 >= value && value2 >= value3)
                {
                return false;
                }


            return true;
        }
        return false;
    }
  public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
     throw new NotImplementedException();
    }

  }

ValueConverter：

  public class myColorErrorConverter : IValueConverter
 {
     public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
     {
        value = "Red";
        return value as string;
     }

     public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
     {
        if (null != value)
        {
            string x = value.ToString();
            if (x == "#FF000000")
            { return false; ; }

        }
        return true;
     }
  }

更新：经过几天的研究，我得出的结论是，这是不可能的，我将使用对所有文本框的多重绑定并检查前景颜色来绑定我的menuItem 。