How can you programmatically order categories in the Xceed PropertyGrid?

Question

As shown in the example here , what I'm trying to achieve is ordering categories in the Xceed PropertyGrid control.

As that example shows (copied here for reference), you can specify this information at compile-time by adding attributes to the class, like so...

[CategoryOrder("General", 1)]
[CategoryOrder("Advanced", 2)]
[CategoryOrder("Other", 3)]
public class MyClass {
    [Category("General")]
    public string Property1 { get; set; }
    [Category("Advanced")]
    public int Property2 { get; set; }
    [Category("Other")]
    public double Property3 { get; set; }
    [Category("General")]
    public string Property4 { get; set; }
    [Category("Advanced")]
    public int Property5 { get; set; }
    [Category("Other")]
    public double Property6 { get; set; }
}

And it would appear in the PropertyGrid like this...

What I'm trying to do however is set the CategoryOrderAttribute values at runtime. Here's what I'm trying, but it's not working...

// Note: This gets executed *prior* to assignment to the PropertyGrid
TypeDescriptor.AddAttributes(typeof(MyClass),
    new CategoryOrderAttribute("General", 1),
    new CategoryOrderAttribute("Advanced", 2),
    new CategoryOrderAttribute("Other", 3)
);

Like I said, this doesn't work and the categories still appear in alphabetical order. Any idea why that doesn't work?

Answer 1

Turns out there are two bugs in the source. One, they aren't overriding TypeID in CategoryOrderAttribute, and two, they aren't using TypeDescriptor.GetAttributes. I've submitted bugs for both...

https://github.com/xceedsoftware/wpftoolkit/issues/1522