sending sms to many numbers using gsm modem in c#

Hello Guyz, i would like to ask how can i send sms to all number attached here is my source code i can only sent a sms to one phone number but i want to send it to many phone number. thanks

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.Data.SqlClient;
//============
using System.IO.Ports;
using System.Threading;
namespace StudentInformationSystem
{
public partial class frmsendingsms : Form
{
SqlCommand cmd;
SqlConnection cn;
SqlDataAdapter da;
SqlDataReader dr;
string _title = "STUDENT INFORMATION SYSTEM";
public frmsendingsms()
{
InitializeComponent();
academicyear();
}
public void academicyear()
{
cn = ClassDB.ConnectDB();
//cn.Open();
cmd = new SqlCommand("select academicyear from tblAY where status like 'OPEN'", cn);
cmd.Parameters.AddWithValue("@academicyear", txtacademicyear.Text);
dr = cmd.ExecuteReader();
dr.Read();
if (dr.HasRows)
{
txtacademicyear.Text = dr["academicyear"].ToString();
// txtacademicterm.Text = dr["term"].ToString();
//cbacademicterm.Text = dr["term"].ToString();
}
else
{
}
dr.Close();
cn.Close();
}
private void btnSend_Click(object sender, EventArgs e)
{
try
{
SerialPort sp = new SerialPort();
sp.PortName = cbportnumber.Text;
sp.Open();
sp.WriteLine("AT" + Environment.NewLine);
Thread.Sleep(100);
sp.WriteLine("AT+CMGF=1" + Environment.NewLine);
Thread.Sleep(100);
sp.WriteLine("AT+CMGS=\"" + txtPhoneNumber.Text + "\"" + Environment.NewLine);
Thread.Sleep(100);
sp.WriteLine(txtMessage.Text + Environment.NewLine);
Thread.Sleep(100);
sp.Write(new byte[] { 26 }, 0, 1);
Thread.Sleep(100);
var response = sp.ReadExisting();
if (response.Contains("ERROR"))
MessageBox.Show("Send failed!", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
else
MessageBox.Show("Message has been sent", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
sp.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
private void txtyear1_TextChanged(object sender, EventArgs e)
{
try
{
txtyear2.Text = (long.Parse(txtyear1.Text) + 1).ToString();
}
catch
{
txtyear2.Clear();
}
txtacademicyear.Text = txtyear1.Text + "-" + txtyear2.Text;
}
private void txtsearch_KeyUp(object sender, KeyEventArgs e)
{
cn = ClassDB.ConnectDB();
listBox1.Visible = true;
listBox1.Items.Clear();
SqlCommand cmd = cn.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd = new SqlCommand("Select* from tblstudentregistration where lrn like'" + txtsearch.Text + "%' or fullname Like '" + txtsearch.Text + "%'", cn);
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
foreach (DataRow dr in dt.Rows)
{
listBox1.Items.Clear();
listBox1.Items.Add(dr["lrn"]).ToString();
// listBox1.Items.Clear();
listBox1.Items.Add(dr["fullname"]).ToString();
}
}
private void txtsearch_KeyDown(object sender, KeyEventArgs e)
{
try
{
cn = ClassDB.ConnectDB();
if (e.KeyCode == Keys.Down)
{
listBox1.Focus();
listBox1.SelectedIndex = 0;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
private void listBox1_KeyDown(object sender, KeyEventArgs e)
{
cn = ClassDB.ConnectDB();
if (e.KeyCode == Keys.Down)
{
this.listBox1.SelectedIndex = this.listBox1.SelectedIndex;
}
if (e.KeyCode == Keys.Up)
{
this.listBox1.SelectedIndex = this.listBox1.SelectedIndex;
}
if (e.KeyCode == Keys.Enter)
{
//search();
txtsearch.Text = listBox1.SelectedItem.ToString();
displayresulttextboxs();
// displayresultontxtboxes();
listBox1.Visible = false;
}
}
private void displayresulttextboxs()
{
cn = ClassDB.ConnectDB();
// cmd = new SqlCommand("Select * from tblstudentregistration where lrn='" + txtsearchstudentlrn0rFullname.Text + "' and academicyear='" + txtacademicyear.Text + "' and academicterm='" + txtacademicterm.Text + "'", cn);
cmd = new SqlCommand("Select * from tblstudentregistration where lrn='" + txtsearch.Text + "' and academicyear='"+txtacademicyear.Text+"' and academicterm ='"+cbacademicterm.Text+"'", cn);
dr = cmd.ExecuteReader();
if (dr.Read())
{
txtsearch.Text = dr[1].ToString();
txtPhoneNumber.Text= dr[9].ToString();
}
else
{
cn = ClassDB.ConnectDB();
// cmd = new SqlCommand("Select * from tblstudentregistration where fullname='" + txtsearchstudentlrn0rFullname.Text + "' and academicyear='" + txtacademicyear.Text + "' and academicterm='" + txtacademicterm.Text + "'", cn);
cmd = new SqlCommand("Select * from tblstudentregistration where fullname='" + txtsearch.Text + "' and academicyear='" + txtacademicyear.Text + "' and academicterm ='" + cbacademicterm.Text + "'", cn);
dr = cmd.ExecuteReader();
if (dr.Read())
{
txtsearch.Text = dr[1].ToString();
txtPhoneNumber.Text = dr[9].ToString();
}
else
{
MessageBox.Show("There's no Record has been found", _title, MessageBoxButtons.OK, MessageBoxIcon.Stop);
}
}
}
private void btnsearch_Click(object sender, EventArgs e)
{
}
}
}

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Rijwan Ansari5y ago
Check this as well
https://www.c-sharpcorner.com/UploadFile/e881fb/send-sms-using-gsm-modem-with-C-Sharp/
0
Rijwan Ansari5y ago
hi,

check this if you can get some idea.
https://www.codeproject.com/Articles/20420/How-To-Send-and-Receive-SMS-using-GSM-Modem-2
0