How to use c# methods with serial port in asp .net core?

Question

I have a task to create web app with ASP .NET core 2.0 where you can communicate with modem and send SMS using AT command. I have a piece of code which can send messages using Serial Port but ASP doesn't have this library so how can I use this code in ASP .NET?
Method:

private SerialPort _serialPort;

    public void SendSms()
    {
        Console.WriteLine("Write phone number");
        string phoneNr = Console.ReadLine();
        Console.WriteLine("Write message");
        string message = Console.ReadLine();

        _serialPort = new SerialPort("COM2", 9600);

        Thread.Sleep(1000);

        _serialPort.Open();

        Thread.Sleep(1000);

        _serialPort.Write("AT+CMGF=1\r");

        Thread.Sleep(1000);

        _serialPort.Write("AT+CMGS=\"" + phoneNr + "\"\r\n");

        Thread.Sleep(1000);

        _serialPort.Write(message + "\x1A");

        Thread.Sleep(1000);

        _serialPort.Close();
    }

Also in my app I have chat window so I want to use input box and button to write and send SMS.

 <form method="post">
            <input asp-for="MessageBody" id="textInput" type="text" placeholder="Enter message..." class="form-control " />
            <button asp-action="SendMessage" id="sendButton" class="btn btn-primary btn-block" type="submit">Send</button>
 </form>

For now SendMessage only saves message into database.
Sorry if my question is formulated not in the best way, writing here for the first time.

Answer 1

Can you try to add "\\n" in this line.

_serialPort.Write("AT+CMGF=1\r");

It should be something like this

_serialPort.Write("AT+CMGF=1\r\n");

Answer 2

Here is the documentation you are looking for Serial port communication in .net core

Example from the link for completeness:

using System;
using System.IO.Ports;
using System.Threading;

public class PortChat
{
static bool _continue;
static SerialPort _serialPort;

public static void Main()
{
    string name;
    string message;
    StringComparer stringComparer = StringComparer.OrdinalIgnoreCase;
    Thread readThread = new Thread(Read);

    // Create a new SerialPort object with default settings.
    _serialPort = new SerialPort();

    // Allow the user to set the appropriate properties.
    _serialPort.PortName = SetPortName(_serialPort.PortName);
    _serialPort.BaudRate = SetPortBaudRate(_serialPort.BaudRate);
    _serialPort.Parity = SetPortParity(_serialPort.Parity);
    _serialPort.DataBits = SetPortDataBits(_serialPort.DataBits);
    _serialPort.StopBits = SetPortStopBits(_serialPort.StopBits);
    _serialPort.Handshake = SetPortHandshake(_serialPort.Handshake);

    // Set the read/write timeouts
    _serialPort.ReadTimeout = 500;
    _serialPort.WriteTimeout = 500;

    _serialPort.Open();
    _continue = true;
    readThread.Start();

    Console.Write("Name: ");
    name = Console.ReadLine();

    Console.WriteLine("Type QUIT to exit");

    while (_continue)
    {
        message = Console.ReadLine();

        if (stringComparer.Equals("quit", message))
        {
            _continue = false;
        }
        else
        {
            _serialPort.WriteLine(
                String.Format("<{0}>: {1}", name, message));
        }
    }

    readThread.Join();
    _serialPort.Close();
}

public static void Read()
{
    while (_continue)
    {
        try
        {
            string message = _serialPort.ReadLine();
            Console.WriteLine(message);
        }
        catch (TimeoutException) { }
    }
}

// Display Port values and prompt user to enter a port.
public static string SetPortName(string defaultPortName)
{
    string portName;

    Console.WriteLine("Available Ports:");
    foreach (string s in SerialPort.GetPortNames())
    {
        Console.WriteLine("   {0}", s);
    }

    Console.Write("Enter COM port value (Default: {0}): ", defaultPortName);
    portName = Console.ReadLine();

    if (portName == "" || !(portName.ToLower()).StartsWith("com"))
    {
        portName = defaultPortName;
    }
    return portName;
}
// Display BaudRate values and prompt user to enter a value.
public static int SetPortBaudRate(int defaultPortBaudRate)
{
    string baudRate;

    Console.Write("Baud Rate(default:{0}): ", defaultPortBaudRate);
    baudRate = Console.ReadLine();

    if (baudRate == "")
    {
        baudRate = defaultPortBaudRate.ToString();
    }

    return int.Parse(baudRate);
}

// Display PortParity values and prompt user to enter a value.
public static Parity SetPortParity(Parity defaultPortParity)
{
    string parity;

    Console.WriteLine("Available Parity options:");
    foreach (string s in Enum.GetNames(typeof(Parity)))
    {
        Console.WriteLine("   {0}", s);
    }

    Console.Write("Enter Parity value (Default: {0}):",             defaultPortParity.ToString(), true);
    parity = Console.ReadLine();

    if (parity == "")
    {
        parity = defaultPortParity.ToString();
    }

    return (Parity)Enum.Parse(typeof(Parity), parity, true);
}
// Display DataBits values and prompt user to enter a value.
public static int SetPortDataBits(int defaultPortDataBits)
{
    string dataBits;

    Console.Write("Enter DataBits value (Default: {0}): ", defaultPortDataBits);
    dataBits = Console.ReadLine();

    if (dataBits == "")
    {
        dataBits = defaultPortDataBits.ToString();
    }

    return int.Parse(dataBits.ToUpperInvariant());
}

// Display StopBits values and prompt user to enter a value.
public static StopBits SetPortStopBits(StopBits defaultPortStopBits)
{
    string stopBits;

    Console.WriteLine("Available StopBits options:");
    foreach (string s in Enum.GetNames(typeof(StopBits)))
    {
        Console.WriteLine("   {0}", s);
    }

    Console.Write("Enter StopBits value (None is not supported and \n" +
     "raises an ArgumentOutOfRangeException. \n (Default: {0}):", defaultPortStopBits.ToString());
    stopBits = Console.ReadLine();

    if (stopBits == "" )
    {
        stopBits = defaultPortStopBits.ToString();
    }

    return (StopBits)Enum.Parse(typeof(StopBits), stopBits, true);
}
public static Handshake SetPortHandshake(Handshake defaultPortHandshake)
{
    string handshake;

    Console.WriteLine("Available Handshake options:");
    foreach (string s in Enum.GetNames(typeof(Handshake)))
    {
        Console.WriteLine("   {0}", s);
    }

    Console.Write("Enter Handshake value (Default: {0}):", defaultPortHandshake.ToString());
    handshake = Console.ReadLine();

    if (handshake == "")
    {
        handshake = defaultPortHandshake.ToString();
    }

    return (Handshake)Enum.Parse(typeof(Handshake), handshake, true);
}

}