Question

I save an output of a command from console.

The output can have more than one line.

How can I search for specific words in all the output ?

Here is my current code:

string buff, ok; 
ok = "OK"; 
SerialPort p = ...
// p initialization...
p.Write("AT+CMGL=\"REC UNREAD\" " + "\r"); 
System.Threading.Thread.Sleep(1000); 
buff = p.ReadExisting(); 
if (buff.Contains(ok)) 
   // do smth

an example of the output:

+CMGL: 10,"REC READ","0372022244",,"12/02/22,08:08:58+08"
2073692066616374757261207661206669206163686974617461206C612074696D702120446574616C696920696E206D6167617A696E656C6520566F6461666F6E6520736175206C612062616E6361206476732E

OK

will this search all the lines from buff for ok ? or just the first line ? i tried it like this and it seems that he can not find “OK” in the output

    namespace SerialTest

{
    public class Program
    {

        public static void Main(string[] args)
        {
            string buff="0";
            string ok = "OK";

            SerialPort p = new SerialPort("COM28");
            p.DataReceived += new SerialDataReceivedEventHandler(p_DataReceived);
            p.Open();
            string line = "1";
            p.Write("AT" + "\r");
            buff = p.ReadExisting();
            p.Write("AT+CMGF=1"+ "\r" );
            buff = p.ReadExisting();

            do
            {
                p.Write("AT+CMGL=\"REC UNREAD\" " + "\r");
                buff = p.ReadExisting();

                if (buff.Contains(ok))
                    Console.WriteLine("Everything is OK");
                else
                    Console.WriteLine("NOK");

                line = Console.ReadLine();
            } while (line != "quit");
            p.Close();
        }

        public static void p_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {

            Console.WriteLine((sender as SerialPort).ReadExisting());
        }
    }
}

Answer 1

p.ReadExisting() does read operations on a SerialPort.

The MSDN documentation says:

Reads all immediately available bytes, based on the encoding, in both
the stream and the input buffer of the SerialPort object.

This means that you might not get all the data you are expecting in one single call to ReadExisting as that data might not ba available yet. You should probably loop through and read all the data from the serial port before doing the Contains check.

On a side note: using Thread.Sleep especially when dealing with serial operations is not a good idea. Instead of sleeping while waiting for the data, use the SerialPort.DataReceived event to read available data.

Try this to correctly read data from your serial port and get rid of the Sleep

String data = "";
p.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);
private static void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
   SerialPort sp = (SerialPort)sender;
   string indata = sp.ReadExisting();
   data += indata;
}

And then have a timer set to check the output after 1 second.
In the timer event handler you check data.Contains("OK");