Generally using a module constructor is not recommended. Please refer to the
article
http://msdn2.microsoft.com/library/ms173266(en-us,vs.80).aspx
which contains in detail what Carl explains on how to do Initialization of
Mixed assemblies.
Thanks,
Kapil

Carl and Kapil.

I added to my DLLs a source file like this:

__gc class QIVCadCctor
{
 public:
   QIVCadCctor()
   {
     System::Threading::Thread::CurrentThread->ApartmentState =
System::Threading::ApartmentState::STA;
   }

   static QIVCadCctor* cadCctor = new QIVCadCctor();
};

Is this right? The constructor will execute during .cctor initialization?

I made this in all DLLs with clr support, but I'm still getting the drag &
drop registration failure.

In fact, I get an exception on my debug output window when I try to set STA
apartment state model:

   Managed Debugging Assistant 'InvalidApartmentStateChange' has detected a
problem in 'c:\Fontes\QiCad.NET\QiCad.NET.exe'.
   Additional Information: Thread is attempting to set the apartment state
to STA, but it has already been set to MTA.
   See
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50215\sdk\bin\mdaBoilerplate.exe.mda.config
for documentation.

Am I missing something?

Thanks for your help.

Adriano.