Following is one example to do this:-
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO.Ports;
using System.Threading;
namespace SMSWinApp
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private SerialPort _serialPort;
private void button1_Click(object sender, EventArgs e)
{
string number = textBox1.Text;
string message = txtMessage.Text;
_serialPort = new SerialPort("COM8", 115200);
Thread.Sleep(100);
_serialPort.Open();
Thread.Sleep(100);
_serialPort.Write("AT+CMGF=1\r");
Thread.Sleep(100);
_serialPort.Write("AT+CMGS=\"" + number + "\"\r\n");
Thread.Sleep(100);
_serialPort.Write(message + "\x1A");
Thread.Sleep(300);
label1.Text = "Message sent !!";
_serialPort.Close();
}
}
}