是否有一种*干净的*方法可以使只读依赖属性反映另一个属性的值？

下面的代码是我当前的解决方案。

我试图模仿的一个很好的例子是 FrameworkElement.ActualWidth 属性。您知道每当 Width 属性更改、或重新绘制控件或其他任何时候，如何计算和重新分配 ActualWidth 属性吗？ ------

从开发人员的角度来看，这看起来就像是在努力进行数据绑定。
但 ActualWidth 是只读依赖属性。微软真的需要经历这个巨大的代码垃圾坑才能实现这一点吗？或者是否有更简单的方法来利用数据绑定系统的现有功能？

public class foo : FrameworkElement
{
    [ValueConversion(typeof(string), typeof(int))]
    public class fooConverter : IValueConverter
    {   public object Convert(  object value, Type targetType,
                                object parameter, CultureInfo culture)
        { ... }
        public object ConvertBack(  object value, Type targetType,
                                    object parameter, CultureInfo culture)
        { ... }
    }

    private static readonly fooConverter fooConv = new fooConverter();



    private static readonly DependencyPropertyKey ReadOnlyIntPropertyKey =
        DependencyProperty.RegisterReadOnly( "ReadOnlyInt", typeof(int),
                                             typeof(foo), null);
    public int ReadOnlyInt
    {   get { return (int)GetValue(ReadOnlyIntPropertyKey.DependencyProperty); }
    }



    public static readonly DependencyProperty ReadWriteStrProperty =
        DependencyProperty.Register( "ReadWriteStr", typeof(string), typeof(foo),
                                     new PropertyMetadata(ReadWriteStr_Changed));
    public string ReadWriteStr
    {   get { return (string)GetValue(ReadWriteStrProperty); }
        set { SetValue(ReadWriteStrProperty, value); }
    }



    private static void ReadWriteStr_Changed(   DependencyObject d,
                                            DependencyPropertyChangedEventArgs e)
    {   try
        {   if (d is foo)
            {   foo f = d as foo;
                f.SetValue( ReadOnlyIntPropertyKey,
                            fooConv.Convert(f.ReadWriteStr, typeof(int), null,
                                            CultureInfo.CurrentCulture));
            }
        }
        catch { }
    }
}

不幸的是，您将需要您所拥有的大部分内容。在这种情况下不需要 IValueConverter，因此您可以将其简化为：

public class foo : FrameworkElement
{
    private static readonly DependencyPropertyKey ReadOnlyIntPropertyKey =
        DependencyProperty.RegisterReadOnly( "ReadOnlyInt", typeof(int),
                                         typeof(foo), null);
    public int ReadOnlyInt
    {
       get { return (int)GetValue(ReadOnlyIntPropertyKey.DependencyProperty); }
    }

    public static readonly DependencyProperty ReadWriteStrProperty =
        DependencyProperty.Register( "ReadWriteStr", typeof(string), typeof(foo),
                                 new PropertyMetadata(ReadWriteStr_Changed));

    public string ReadWriteStr
    {
       get { return (string)GetValue(ReadWriteStrProperty); }
        set { SetValue(ReadWriteStrProperty, value); }
    }

    private static void ReadWriteStr_Changed(DependencyObject d,
                                        DependencyPropertyChangedEventArgs e)
    {
         foo f = d as foo;
         if (f != null)
         {
              int iVal;
              if (int.TryParse(f.ReadWriteStr, out iVal))
                  f.SetValue( ReadOnlyIntPropertyKey, iVal);
         }
    }
}