Question

I’m using following code to send sms throuh gsm modem

for (int i = 0; i < 10; i++)
        {
            MSComm1.CommPort = 3;
            MSComm1.PortOpen = true;
            MSComm1.Output = "AT" + '\r' + '\n';
            Thread.Sleep(1000);
            MSComm1.Output = "AT+CMGF=1" + '\r' + '\n';
            Thread.Sleep(1000);
            MSComm1.Output = "AT+CMGS=" + '\"' + MobileNo + '\"' + '\r' + '\n';
            Thread.Sleep(1000);
            MSComm1.Output = MsgTxt + (char)26;
            Thread.Sleep(1000);
            MSComm1.PortOpen = false;
        }

my question is:
i want to open the port as in (MSComm1.CommPort = 3;) only if it is not already opened. so that i don’t have to open and close it again and again for each sms as in the above loop

Answer 1

You should ditch the MSComm ActiveX control if you’re using any language/framework designed in the last decade or if you’d like your application to run on new or newer machines/Operating Systems.

Instead you can use the SerialPort class provided in the .Net Framework:

using (var com3 = new SerialPort("COM3"))
{
    if (!com3.IsOpen) com3.Open();

    for (int ii = 0; ii < 10; ++ii)
    {
        com3.WriteLine("AT" + Environment.NewLine);
        com3.WriteLine("AT+CMGF=1" + Environment.NewLine);
        com3.WriteLine("AT+CMGS=\"" + 03152800485 + "\"" + Environment.NewLine);
        com3.WriteLine("Hello Kashif" + (char)26);
        Thread.Sleep(5000);
    }
    com3.Close();
}