Topic: How to P/Invoke acdbGetCurVportTableRecordId for AutoCAD 2008?

[csharpbird]

Code: [Select]

[DllImport("acdb17.dll", CallingConvention = CallingConvention.Cdecl, EntryPoint = "?acdbGetCurVportTableRecordId@@YA?AVAcDbObjectId@@PAVAcDbDatabase@@@Z")]
        private extern static ObjectId acdbGetCurVportTableRecordId(IntPtr dbObject);
        public static ObjectId CurrentViewportTableRecordId(this Database db)
        {
            return acdbGetCurVportTableRecordId(db.UnmanagedObject);
        }
When i call the CurrentViewportTableRecordId function,I get System.AccessViolationException exception.
Any help?