Start timer from another thread

Question

I am working on a project which will receive command from telnet and start a timer.
In the sock function, I use form reference to call timer.start(), but timer control cannot start Tick event:
Here is code for sock functin after receive the command:
 static void appServer_NewRequestReceived(AppSession session, StringRequestInfo requestInfo)
            switch (requestInfo.Key.ToUpper())
                case ("START"):
                    session.Send(requestInfo.Body);
                    changetimer(1, requestInfo.Body);
break;}}
Here is the function to call timer start:
  static void changetimer(int action, string incomingmsg)
            //timer1.Start();
            Form1 frm = (Form1)Application.OpenForms["form1"];
            switch (action)
                case 1:
                     frm.timer1.Start();
                     break;
                case 2:
                    frm.timer1.Stop();
                    break;
and this is timer tick :
private void timer1_Tick(object sender, EventArgs e)
            TimeSpan result = TimeSpan.FromSeconds(second);
            string fromTimeString = result.ToString();
            label1.Text = fromTimeString;
            second = second + 1;

Answer 1

You should start the timer on the UI thread. You could use the Invoke method to access a UI element from another thread:
static void changetimer(int action, string incomingmsg)
//timer1.Start();
Form1 frm = (Form1)Application.OpenForms["form1"];
switch (action)
case 1:
frm.Invoke(new Action(() => { frm.timer1.Start(); }));
break;
case 2:
frm.Invoke(new Action(() => { frm.timer1.Stop(); }));
break;
Hope that helps.
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