VS IntelliSense - IFluentInterface / IHideObjectMembers trick does not work. Why?

Question

The IHideObjectMembers trick (a.k.a IFluentInterface) can be used e.g. in fluent interface implementations to hide System.Object members from IntelliSense. (If you don't know this trick, you can read up on it via the above link; I'm just repeating the interface's usual declaration here:)

using System;
using System.ComponentModel;

[EditorBrowsable(EditorBrowsableState.Never)]
public interface IHideObjectMembers
{
    [EditorBrowsable(EditorBrowsableState.Never)] bool Equals(object obj);
    [EditorBrowsable(EditorBrowsableState.Never)] int GetHashCode();
    [EditorBrowsable(EditorBrowsableState.Never)] Type GetType();
    [EditorBrowsable(EditorBrowsableState.Never)] string ToString();
}

I'm now supposed to be able to hide System.Object members on another type as follows:

public class SomeClass : IHideObjectMembers { ... }

or:

public interface ISomeInterface : IHideObjectMembers { ... }

I tried this in both VS 2008 Express and VS 2008 Standard. However, no members are hidden from IntelliSense at all. I have used the EditorBrowsableAttribute in different projects and it always worked well; however, it doesn't work in this particular scenario.

If things had worked as expected, I would only have seen the SomeMethodTwo method.

Am I missing something?

---

P.S.: You can infer my example code from the declarations and the screenshot. I have a class SomeClass with a single dummy method called SomeMethodTwo. Very simple. I have not re-implemented the four System.Object methods in this class, as this should not be necessary.

Answer 1

Before a working solution was posted (see above), I researched and experimented a bit, and found out this:

• IntelliSense needs to be told to ignore properties marked with an EditorBrowsableState equalling Advanced or Never. This is achieved in Visual Studio via the menu item Tools → Options... → Text editor → C# → IntelliSense → Hide advanced members.

• The IHideObjectMembers trick works only from "other" assemblies, and only when the project that makes use of IHideObjectMembers is not loaded in the same solution.

• Hiding non-static members of object sometimes doesn't work when done via a IHideObjectMembers interface, but it works when the methods are explicitly overridden directly in the class... which unfortunately makes the shown hiding technique less useful.

Sources of these clues:

• Blog article How to keep the Intellisense info box short and tidy on exdream.com.

• The MSDN reference page for System.ComponentModel.EditorBrowsableAttribute.

Answer 2

The trick works if you don't use

var x = new SomeClass();

but explicitely use the interface that inherits from IHideObjectMembers

ISomeInterface x = new SomeClass();

var takes the Type of the concrete class. Thus IntelliSense will look for object.ToString() and not IHideObjectMembers.ToString(). The former is not decorated with the EditorBrowsableAttribute while the later is.

Daniel Cazzulino explicitely refers to interfaces in his post

we’ve done this with all the interfaces in our fluent API

Answer 3

This trick only works when you are using types that are included in referenced DLLs. These referenced assemblies cannot be Visual Studio project references. If you reference the DLL themselves, then the trick should work for you.