使用附加属性代替多绑定

在WPF中，可以使用附加属性来代替多绑定。为Polygon元素创建新的附加属性，绑定这些属性来设置点的x和y坐标。在这种情况下，可以使用PointCollectionConverter将字符串转换为PointCollection对象，这样便可以将Point列表转换为适当的点集合。

代码示例：

public static class PolygonExtension
{
    public static readonly DependencyProperty PointsStringProperty =
        DependencyProperty.RegisterAttached("PointsString",
            typeof(string),
            typeof(PolygonExtension),
            new FrameworkPropertyMetadata(null, OnPointsStringChanged));

    public static string GetPointsString(DependencyObject obj)
    {
        return (string)obj.GetValue(PointsStringProperty);
    }

    public static void SetPointsString(DependencyObject obj, string value)
    {
        obj.SetValue(PointsStringProperty, value);
    }

    private static void OnPointsStringChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
    {
        string pointsString = e.NewValue as string;
        if (!string.IsNullOrEmpty(pointsString))
        {
            PointCollection points = (PointCollection)new PointCollectionConverter().ConvertFromString(pointsString);
            Polygon polygon = obj as Polygon;
            if (polygon != null)
            {
                polygon.Points = points;
            }
        }
    }
}

使用示例：