// --------------------------------- RunCommand ------------------------------
        public virtual string[] RunCommand(
            CommandThread InCmdThread,
            ReadBuffer InReadBuffer,
            delWriteEventLog InWriteEventLog,
            string InCmdText)
        {
            StringBuilder accumRead = new StringBuilder();

            string[] lines = null;

            // send command to the telnet server.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                if (InWriteEventLog != null)
                {
                    InWriteEventLog(null, "exit", "Logout");
                }
                InCmdThread.Conn.WriteLine(InCmdText);
            }

            // read back whatever is in the read buffer.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                lines = InReadBuffer.ReadUntilEndsWith(CommandPromptPatterns);
                ThreadCommon.WriteToEventLog(InWriteEventLog, lines, "Run");
            }

            // return all the response line received from the server.
            return(lines);
        }
        // --------------------------------- Logout ------------------------------
        public virtual string[] Logout(
            CommandThread InCmdThread,
            ReadBuffer InReadBuffer,
            delWriteEventLog InWriteEventLog,
            string InNullText)
        {
            StringBuilder accumRead = new StringBuilder();

            string[] lines = null;

            if (InCmdThread.Conn.IsConnected == false)
            {
                InCmdThread.ShutdownFlag.Set();
            }

            // send "exit" command to the telnet server.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                if (InWriteEventLog != null)
                {
                    InWriteEventLog(null, "exit", "Logout");
                }
                try
                {
                    InCmdThread.Conn.WriteLine("exit");
                }
                catch (NotConnectedException)
                {
                    InCmdThread.ShutdownFlag.Set();
                }
            }

            // read back whatever is in the read buffer.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                lines = InReadBuffer.Read();
                ThreadCommon.WriteToEventLog(InWriteEventLog, lines, "Logout");
            }

            // wait for the "socket is disconnected" signal.
            int waitDur = 5000;

            while (true)
            {
                bool rc = InCmdThread.Conn.IsDisconnectedSignal.WaitOne(waitDur);
                if (rc == true)
                {
                    break;
                }
                if (waitDur < 3600000)
                {
                    waitDur *= 2;
                }
                InWriteEventLog(null,
                                "waiting for telnet server to disconnect after exit", "Logout");
            }

            // return all the response line received from the server.
            return(lines);
        }
        // --------------------------------- Login ------------------------------
        public virtual string[] Login(
            CommandThread InCmdThread,
            ReadBuffer InReadBuffer,
            delWriteEventLog InWriteEventLog,
            string InNullText)
        {
            StringBuilder accumRead = new StringBuilder();

            string[] lines        = null;
            string[] loginPrompts = new string[] { ":" };

            // telnet server sends a login prompt. read until it arrives.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                if (InWriteEventLog != null)
                {
                    InWriteEventLog(null, "Read login prompt ...", "Login");
                }
                lines = InReadBuffer.ReadUntilEndsWith(loginPrompts);
                ThreadCommon.WriteToEventLog(InWriteEventLog, lines, "Login");
            }

            // send username to the telnet server.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                if (InWriteEventLog != null)
                {
                    InWriteEventLog(null, "Username " + mLoginProperties.LoginUser, "Login");
                }
                InCmdThread.Conn.WriteLine(mLoginProperties.LoginUser);
            }

            // read back the prompt for password.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                if (InWriteEventLog != null)
                {
                    InWriteEventLog(null, "Read password prompt ...", "Login");
                }
                lines = InReadBuffer.ReadUntilEndsWith(loginPrompts);
                ThreadCommon.WriteToEventLog(InWriteEventLog, lines, "Login");
            }

            // send password to telnet server.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                if (InWriteEventLog != null)
                {
                    InWriteEventLog(null, "Password ********", "Login");
                }
                InCmdThread.Conn.WriteLine(mLoginProperties.LoginPass);
            }

            // read back until the logged in command prompt.
            if (InCmdThread.ShutdownFlag.State == false)
            {
                if (InWriteEventLog != null)
                {
                    InWriteEventLog(null, "Read command prompt ...", "Login");
                }


                while (true)
                {
                    string[] xx = null;
                    xx = InReadBuffer.Read();
                    ThreadCommon.WriteToEventLog(InWriteEventLog, xx, "Login");
                    string lastLine = Arrayer.LastItem(xx);
                    if (lastLine != null)
                    {
                        string trimLastLine = lastLine.TrimEnd(new char[] { ' ', '\t', '\r', '\n' });
                        string lsChar       = StringExt.Tail(trimLastLine, 1);
                        if (lsChar == ">")
                        {
                            break;
                        }
                    }
                }
            }

            // return all the response line received from the server.
            return(lines);
        }