Hi there.  I have a COM DLL that I have converted into an interop assembly
via the tlbimp.exe tool.  One function that I am trying to use now in C# has
a default parameter defined in my IDL file:

HRESULT Convert( [in, defaultvalue( "" )] BSTR file, [out, retval] long
*count  );

When I try to make use of the function in C# I get a compiler error saying
that this function does not take 0 parameters.
using the ildasm.exe to take a look at the assembly code I get:

.method public hidebysig newslot virtual
       instance int32  Convert([in][opt] string  marshal( bstr) file)
runtime managed internalcall
{
 .custom instance void
[mscorlib]System.Runtime.InteropServices.DispIdAttribute::.ctor(int32) = (
01 00 09 00 00 00 00 00 )
 .param [1] = ""
 .override MYINTEROP:Convert
}

It looks to me like the parameter is optional and that it is indeed setting
a default value of "".  Do I have to do something else for C# to recognize
this?  It is not that big of a deal to pass a value to the function( I would
prefer not to ), but it seems like there should be all that is needed for C#
to fill in the value if it isn't there.  Any help is appreciated.  Thank you
for your time.

-Mac