Hi,

We have .NET dlls containing interfaces that we want to use from COM. Each
interface has a Guid Attribute specifying its Interface ID. We use regasm in
order to generate the tlb and then use the DLL as COM #import statement in a
C++ project .

For some reason, when the tlb is generated, interface inheritance is not
applied to the generated IDL. For example, if we have two interfaces:

<C# Code Class Lib>

namespace Foo

{

[
System.Runtime.InteropServices.Guid("C5DDC244-4CFC-4f15-821B-787F9C0684D5")
]

public interface A

{

string FirstName{get;}

}

[
System.Runtime.InteropServices.Guid("97286132-A545-4965-9BE3-AC3E2C63ED9E")
]

public interface B : A

{

string LastName{get;}

}

}

<C# Code Class Lib/>

The generated IDL in the type lib will not show the inheritance :

<Generated IDL from TLB>

// Generated .IDL file (by the OLE/COM Object Viewer)

//

// typelib filename: <could not determine filename>

[

uuid(89C9460C-048D-3C45-916C-8032C40350AB),

version(1.0),

custom(90883F05-3D28-11D2-8F17-00A0C9A6186D, ClassLibrary1,
Version=1.0.1642.16217, Culture=neutral, PublicKeyToken=null)

]

library ClassLibrary1

{

// TLib : // TLib : OLE Automation : {00020430-0000-0000-C000-000000000046}

importlib("stdole2.tlb");

// Forward declare all types defined in this typelib

interface A;

interface B;

[

odl,

uuid(C5DDC244-4CFC-4F15-821B-787F9C0684D5),

version(1.0),

dual,

oleautomation,

custom(0F21F359-AB84-41E8-9A78-36D110E6D2F9, Foo.A)

]

interface A : IDispatch {

[id(0x60020000), propget]

HRESULT FirstName([out, retval] BSTR* pRetVal);

};

[

odl,

uuid(97286132-A545-4965-9BE3-AC3E2C63ED9E),

version(1.0),

dual,

oleautomation,

custom(0F21F359-AB84-41E8-9A78-36D110E6D2F9, Foo.B)

]

interface B : IDispatch {

[id(0x60020000), propget]

HRESULT LastName([out, retval] BSTR* pRetVal);

};

};

<Generated IDL from TLB/>

Is there a way to have interface B derived from interface A in the IDL?

What is the proper way to have the inheritance reflected in the tlb file?

Thanks,

Eric