I want to call the function without a parameter so the entire recordset is returned.

I am trying to call an ActiveX DLL written in VB6 from my C# app. The function call has a single parameter that is declared optional. How do I call it from C#? The VB function is: Public Function GetTasks(Optional ByVal lngUserCode As Long) As ADODB.Recordset

Thanks for the reply. The problem is that the only place the dll is displayed is on the COM tab. I don't see how you remove a reference using that dialog box. I used the Browse window to find the interop assembly and deleted the file thru that dialog. But the project still builds OK so that did not remove the reference. Your statment 2) says "remove the dll". Which tab are you referring to? Where exactly am I viewing the dll to remove it? I have since found the references in the solution explorer. I can remove the dll reference there. But for my understanding, I would like to duplicate your method.

I have an VB ActiveX DLL with a function the receives a string parameter. I want to call this function from C#. I made a reference to the DLL in my VS 2003 project. DLL Function -------------- public function ShowMsg (strIn as String) msgbox strIn end function C# Function Call ------------------ string str1 = "ABCD"; Class7 s = new Class7Class(); s.ShowMsg(str1); When I call the function from C#, I get an error: Argument '1': cannot convert from 'byte[]' to 'ref string' How do I marshal a C# string to an ActiveX DLL string? Thanks, Rg

I found the reference in the solution explorer and removed it there.

I built the DLL (Message.dll) using VB6 as an ActiveX DLL. In VS 2003: I used the Add Reference utility, COM tab to select the DLL and add it to my project. Intellisense shows me the single function I created in the DLL. I then added functions to the DLL and I want to reference them in my C# code. The IDE tells me I need to remove the reference to the old DLL before I can use the new one. I see the Interop.Message.dll in the bin-Debug directory of my project. I assume something needs to be removed/unregistered from the project before I can reference the DLL but I don't see how to perform the task.

I have a C# project that references an ActiveX DLL. I have registered the DLL using the VS IDE. I want to make some changes to the DLL and consequently register the new version with the IDE. 1. How do I remove the existing reference so I can register the new DLL? 2. Where do I see the registered files for a given project? Thanks, Rg

If you are not limited to mfc, you will find ActiveX development much quicker using Visual Basic 6. Much of the lower level work is done for you and you can concentrate on your application specifics.