如何获得属性网格，以允许编辑对象的多选择

当使用属性网格时，我如何让它允许我一次为多个对象设置一个属性(当有第二层时)。如果两个属性具有相同的值，一切似乎都可以正常工作，但如果属性不等于propertygrid不加载子属性(从箭头向右)，因此它们无法设置。我创建了下面的例子，很抱歉代码太长了。

    public partial class Form1 : Form
{
    public Form1()
    {
        this.Size = new Size(275, 568);
        PropertyGrid grid = new PropertyGrid();
        grid.Dock = DockStyle.Fill;
        this.Controls.Add(grid);

        Control c1 = new Control();
        c1.Border.Bottom.Color = Color.Red;
        Control c2 = new Control();
        c2.Border.Bottom.Color = Color.Red;
        Control c3 = new Control();
        c3.Border.Bottom.Color = Color.Purple;
        //This works as expected
        //grid.SelectedObject = c1;
        //This works as expected
        //grid.SelectedObjects = new object[] { c1, c2 };
        //This does not work
        grid.SelectedObjects = new object[] { c1, c3 };
    }
}
class Control
{
    public Control()
    {
        Border = new Border();
        Text = "Text";
    }
    public string Text { get; set; }
    [TypeConverter(typeof(BorderConverter))]
    public Border Border { get; set; }
}
class Border
{
    public Border()
    {
        Top = new Line();
        Bottom = new Line();
        Right = new Line();
        Left = new Line();
    }
    [TypeConverter(typeof(LineConverter))]
    public Line Top { get; set; }
    [TypeConverter(typeof(LineConverter))]
    public Line Left { get; set; }
    [TypeConverter(typeof(LineConverter))]
    public Line Bottom { get; set; }
    [TypeConverter(typeof(LineConverter))]
    public Line Right { get; set; }
    public override bool Equals(object obj)
    {
        if ((obj as Border) == null)
            return false;
        Border b = (Border)obj;
        return b.Left.Equals(Left) &&
            b.Right.Equals(Right) && b.Top.Equals(Top)
            && b.Bottom.Equals(Bottom);
    }
    public override int GetHashCode()
    {
        return base.GetHashCode();
    }
}
public class BorderConverter
: TypeConverter
{
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
    {
        return base.CanConvertFrom(context, sourceType);
    }
    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        return ((destinationType == typeof(InstanceDescriptor)) || base.CanConvertTo(context, destinationType));
    }
    public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)
    {
        return attributes == null ? TypeDescriptor.GetProperties(value) : TypeDescriptor.GetProperties(value, attributes);
    }
    public override bool GetPropertiesSupported(ITypeDescriptorContext context)
    {
        return true;
    }
}
class Line
{
    public Line()
    {
        Color = Color.Black;
        Wieght = 0;
    }
    public Color Color { get; set; }
    public int Wieght { get; set; }
    public override bool Equals(object obj)
    {
        if ((obj as Line) == null)
            return false;
        Line l = (Line)obj;
        return l.Color == Color && l.Wieght == Wieght;
    }
    public override int GetHashCode()
    {
        return base.GetHashCode();
    }
}
public class LineConverter
: TypeConverter
{
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
    {
        return base.CanConvertFrom(context, sourceType);
    }
    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        return ((destinationType == typeof(InstanceDescriptor)) || base.CanConvertTo(context, destinationType));
    }
    public override object CreateInstance(ITypeDescriptorContext context, IDictionary propertyValues)
    {
        if (propertyValues == null) throw new ArgumentNullException("propertyValues");
        try
        {
            Line bs = new Line();
            bs.Color = (Color)propertyValues["Color"];
            bs.Wieght = (int)propertyValues["Wieght"];
            return bs;
        }
        catch (Exception ex) { throw new Exception("Invalid Property value.", ex); }
    }
    public override bool GetCreateInstanceSupported(ITypeDescriptorContext context)
    {
        return true;
    }
    public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)
    {
        return attributes == null ? TypeDescriptor.GetProperties(value) : TypeDescriptor.GetProperties(value, attributes);
    }
    public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
    {
        return base.GetStandardValuesSupported(context);
    }
    public override bool GetPropertiesSupported(ITypeDescriptorContext context)
    {
        return true;
    }
}