[DllImport("odbc32.dll")]
        internal static extern int SQLDataSources(int EnvHandle, int Direction, StringBuilder ServerName, int ServerNameBufferLenIn, 
            ref int ServerNameBufferLenOut, StringBuilder Driver, int DriverBufferLenIn, ref int DriverBufferLenOut);
        [DllImport("odbc32.dll")]
        internal static extern int SQLAllocEnv(ref int EnvHandle);

        public static List<ODBC_System_DSN_Entry> ListODBCsources()
        {
            List<ODBC_System_DSN_Entry> entries = new List<ODBC_System_DSN_Entry>();
            int envHandle = 0;
            const int SQL_FETCH_NEXT = 1;
            const int SQL_FETCH_FIRST_SYSTEM = 32;

            if (SQLAllocEnv(ref envHandle) != -1)
            {
                int ret;
                StringBuilder serverName = new StringBuilder(1024);
                StringBuilder driverName = new StringBuilder(1024);
                int snLen = 0;
                int driverLen = 0;
                ret = SQLDataSources(envHandle, SQL_FETCH_FIRST_SYSTEM, serverName, serverName.Capacity, ref snLen,
                            driverName, driverName.Capacity, ref driverLen);
                while (ret == 0)
                {
                    entries.Add(new ODBC_System_DSN_Entry(serverName.ToString(), driverName.ToString()));
                    ret = SQLDataSources(envHandle, SQL_FETCH_NEXT, serverName, serverName.Capacity, ref snLen,
                            driverName, driverName.Capacity, ref driverLen);
                }
                return entries;
            }
            return null;
        }

        public struct ODBC_System_DSN_Entry
        {
            internal String _server;
            internal String _driver;
            internal ODBC_System_DSN_Entry(String server, String driver)
            {
                _server = server;
                _driver = driver;
            }
            public String Server { get { return _server; } }
            public String Driver { get { return _driver; } }
        }