Where is "Inherits <baseclass>" in an Interop UserControl?

Question

I'm looking at the Interop UserControl mechanism that's part of the "Interop Forms Toolkit" version 2.0. (This you to build a .Net UserControl that can be published as a COM object for use on VB6 forms.)

I've started a new project using the "VB6 Interop UserControl" template, and what I see is a class definition that looks like this:

    <ComClass(InteropUserControl.ClassId, InteropUserControl.InterfaceId,       
        InteropUserControl.EventsId)> _
    Public Class InteropUserControl

  + VB6 Interop Code

        'Please enter any new code here, below the Interop code

    End Class

without any "Inherits" statement. But if I look in the Class Browser, I can see that this class (not surprisingly) inherits from the WinForms UserControl class. How can it be that the "Inherits UserControl" piece of the class declaration isn't visible anywhere?

Question 634559 also shows an InteropUserControl class declaration without any "inherits UserControl" statement. I must be missing something simple from my VB.Net knowledge. (I do most of my .Net work in C#.)

Any help in understanding this would be appreciated.

Answer 1

I believe <ComClass()> acts as a signal to the compiler to add some interfaces.

I've found one source for that behavior.

It's possible that a similiar rewrite occurs for Inherits in this case.

Answer 2

The VB.Net compiler adds Inherits UserControl automatically. Take a look at your class using Reflector to see this. In addition to this, it adds Implements _InteropUserControl. So when you write your class like this:

<ComClass(InteropUserControl.ClassId, InteropUserControl.InterfaceId,
    InteropUserControl.EventsId)> _
Public Class InteropUserControl

    ...

It'll come out looking something like this in Reflector:

<DesignerGenerated(), ComClass("a2ee6169-9a0d-4930-b8bb-ee71307c43b3",
    "75ff3d57-6448-40ac-a294-68252180cacd", "2b04895c-43f8-44b3-b187-00556ef53a6a"),
    Guid("a2ee6169-9a0d-4930-b8bb-ee71307c43b3"),
    ClassInterface(ClassInterfaceType.None),
    ComSourceInterfaces("VBControl.InteropUserControl+__InteropUserControl")> _
Public Class InteropUserControl
    Inherits UserControl
    Implements _InteropUserControl

    ...