PropertyDescriptor and Attributes

Question

I have inherited the PropertyDescriptor class to provide kind of 'dynamic' properties. I'm adding some attributes to the PropertyDescriptor. This works perfectly.

When displaying a object in a PropertyGrid, the ReadOnlyAttribute works, but the EditorAttribute doesn't work!

internal class ParameterDescriptor: PropertyDescriptor {
    //...
    public ParameterDescriptor(/* ... */) {
        List<Attribute> a = new List<Attribute>();
        string editor = "System.ComponentModel.Design.MultilineStringEditor,System.Design";
        //...
        a.Add(new ReadOnlyAttribute(true));                         // works
        a.Add(new DescriptionAttribute("text"));                    // works
        a.Add(new EditorAttribute(editor, typeof(UITypeEditor)));   // doesn't work!
        //...    
        this.AttributeArray = a.ToArray();
    }
}

The object that is displayed uses a inherited TypeConverter:

public class ParameterBoxTypeConverter: TypeConverter {
    public override bool GetPropertiesSupported(ITypeDescriptorContext context) {
        return true;
    }

    public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes) {
        List<PropertyDescriptor> desc = new List<PropertyDescriptor>();
        //...
        ParameterDescriptor d = new ParameterDescriptor(/* ... */);
        desc.Add(d);
        //....
        return new PropertyDescriptorCollection(desc.ToArray());
    }

I'm stuck, because the PropertyGrid simply isn't showing anything (I expected a "..." at the property value). And it seems there's no way to debug!

So how can I find what's wrong here?
Is there a way to debug into the PropertyGrid, etc?

Answer 1

From a few quick tests, the name needs to be fuly qualified:

const string name = "System.ComponentModel.Design.MultilineStringEditor, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a";
attribs.Add(new EditorAttribute(name, typeof(UITypeEditor)));

Internally, it uses Type.GetType, and:

var type1 = Type.GetType("System.ComponentModel.Design.MultilineStringEditor, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a");
// ^^^ not null
var type2 = Type.GetType("System.ComponentModel.Design.MultilineStringEditor, System.Design");
// ^^^ null

Of course, you could just use:

attribs.Add(new EditorAttribute(typeof(MultilineStringEditor), typeof(UITypeEditor)));

Alternatively, you can override GetEditor and do whatever your want.