c# - GSM communication, cross threading -

i'm bit new in c# programming somehow managed pickup project requires great skill , knowledge gsm (sms) communication using serialport.

using system; using system.collections.generic; using system.componentmodel; using system.drawing; using system.data; using system.linq; using system.text; using system.threading.tasks; using system.windows.forms; using system.io.ports;  namespace smsget {     public partial class smslogpanel : usercontrol     {         #region default constructor         public smslogpanel()         {             initializecomponent();             serialport1 = new serialport();             serialport1.databits = 8;             serialport1.dtrenable = true;             serialport1.encoding.equals("iso-8859-1");             serialport1.handshake = handshake.requesttosend;             serialport1.parity = parity.none;             serialport1.writetimeout = 300;             serialport1.stopbits = stopbits.one;             checklink();         }     #endregion     #region checking communication , setting user controls...     private void checklink()     {         getvalues value = new getvalues();         string com = value.getport();         int baud = value.getbaud();         int timeot = value.gettimeout();         serialport1.portname = com;         serialport1.baudrate = baud;         serialport1.readtimeout = timeot;          serialport1.open();         if (serialport1.isopen)         {             label1.visible = true;         }         else         {             messagebox.show("komunikacija sa modemom se ne može uspostaviti, molimo postavite novu konfiguraciju...!");             this.controls.clear();             smsconfigpanel cfg = new smsconfigpanel();             cfg.show();             this.controls.add(cfg);         }         serialport1.close();     }     #endregion     #region setiranje timer-a...     private void timer1_tick(object sender, eventargs e)     {         timer1.stop();         execcommand();         timer1.start();     }     #endregion     #region seting handler , executing @ commands     public void execcommand()     {         serialport1.datareceived += new serialdatareceivedeventhandler(getresponse);         serialport1.open();         //prazni se buffer da se ne pokupe neke vrijednosti koje ne trebaju...         serialport1.discardinbuffer();          if (!serialport1.isopen)         {             messagebox.show("modem nije spojen, molimo provjerite konfiguraciju...!");             timer1.stop();         }         serialport1.write("at+cmgf=1" + (char)(13));         serialport1.write("at+cmgl=\"all\"" + (char)(13));     }     public void getresponse(object sender, serialdatareceivedeventargs e)     {         serialport serport = (serialport)sender;         string input = serport.readexisting();         if (input.contains("error"))         {             //textbox2.text = "";         }         else if (input.contains("+cmti:"))         {             serialport1.write("at+cmgf=1" + (char)(13));             serialport1.write("at+cmgl=\"all\"" + (char)(13));         }         else if (input.contains("+cmgl:"))         {             textbox1.text = input;         }         else         {             return;         }         serialport1.close();     }     #endregion } 

}

i think somehow managed create bugs in these areas (not opening/closing serialport1 ports, input data in getresponse(object sender, serialdatareceivedeventargs e) uses separate thread cannot passed textbox1 due cross thread issue..., , wrong @ command reading unreaded messages has been received...)

if can me this, grateful...

thank , best regards.

reason cross thread exception:

you trying update gui element on thread other 1 on created. not allowed.

solution:

to avoid cross thread exception. should update code this

this.invoke((methodinvoker) delegate     {         // update textbox here      });