Passing a Recordset from VB6 to VB.Net (QueryInterface failed.)

[adam]

I am getting an error when trying to use an ADODB.Recordset that was passed
from a VB6 application to a VB.Net class library using COM Interop. I am
running this on WinXP SP2 using the .Net Framework 1.1 and MDAC 2.8 SP1.

This is what I've done:
- I compiled the VB.Net DLL and registered it so it can be used in the VB6
app using "regasm /tlb:VBNETClass. tlb VBNETClass.dll" .
- From the VB6 app, I added a reference to the VB.Net DLL.
- I added references to the ADO 2.8 Library from both the VB6 app and the
VB.Net library. (I also tried ADO 2.6 and 2.7 later but they had the same
results.)
- I built the VB6 EXE and copied it to the directory containing the VB.Net
DLL.

When I run the VB6 EXE, all of the message boxes appear fine except for the
one on the last line of PrintRecordCoun t below. Instead, I get the following
error:

- - - -
Run-time error '-2147467262 (80004002)';
QueryInterface for interface ADODB._Recordse t failed.
- - - -
(The debugger shows it to be a System.InvalidC astException.)

Any ideas?
VB6 APP

Private Sub Command1_Click( )

Dim ccw As New VBNETClass.Clas s1

Dim rs As New ADODB.Recordset
Set rs = CreateObject("A DODB.Recordset" )
rs.CursorType = adOpenStatic
rs.CursorLocati on = adUseClient
rs.Fields.Appen d "FieldName1 ", adVarChar, 10
rs.Fields.Appen d "FieldName2 ", adInteger
rs.Open

rs.AddNew
rs("FieldName1" ) = "David"
rs("FieldName2" ) = 17
rs.Update

rs.Sort = "FieldName2 "
rs.MoveFirst

MsgBox ("In VB6 App, about to call VB.Net class...")
' this line works
MsgBox ("In VB6 Class, rs.RecordCount = " & rs.RecordCount)

ccw.PrintRecord Count (rs)

End Sub

VB.NET CLASS LIBRARY (VBNETClass)

Public Class Class1
Public Function PrintRecordCoun t(ByVal rs As ADODB.Recordset )

MsgBox("In VB.Net Class, about to display RecordCount... ")
' this line produces the error
MsgBox("In VB.Net Class, rs.RecordCount = " & rs.RecordCount)

End Function
End Class

(I also tried changing the type of the input parameter to
ADODB.Recordset Class and ADODB._Recordse t but the same error resulted.)