I need to build a C# dll which reads/writes File Geodatabases using version 9.3 of ArcGIS... is this possible and if so what libraries should I use?

[PaulCleverley]

I have ArcGIS 9.3 installed and Microsoft Visual Studio 2010. I have existing file .gdb databases which I need to be able to read and write. Ideally this would be from a DLL which can be called from managed console applications.

I have got as far as 

IWorkspaceFactory pWorkspaceFactory;
IWorkspace2 m_pWorkspace;
IFeatureWorkspace m_pFWorkspace;

...

pWorkspaceFactory = new FileGDBWorkspaceFactoryClass();
if (pWorkspaceFactory.IsWorkspace(gdbPath))
{
    m_pWorkspace = (IWorkspace2)pWorkspaceFactory.OpenFromFile(gdbPath, 0);
}

the OpenFromFile method fails with "Exception from HRESULT: 0x80040228"

There are other questions about this but they all relate to later versions and I can't see that 9.3 allows the solutions offered there.

Any help gratefully received!

[LanceShipman]

I'm sorry to say that the File Geodatabase API does not support pre-10.0 File Geodatabases. The api was built on top of the 10.0 structure and it's not compatible.