public partial class Form1 : Form

    {

        int count = ;

        System.Timers.Timer timer;

        public Form1()

        {

            InitializeComponent();

            timer = new System.Timers.Timer();

            timer.Interval =  * ;

            timer.Elapsed += (x, y) =>

            {

                count++;

                InvokeMethod(string.Format("{0} count:{1}", DateTime.Now.ToString("HH:mm:ss"), count));

            };

        }

        private void InvokeMethod(string txt)

        {

            Action<string> invokeAction = new Action<string>(InvokeMethod);

            if (this.InvokeRequired)

            {

                this.Invoke(invokeAction, txt);

            }

            else

            {

                txtLog.Text += txt + Environment.NewLine;

            }

        }

        private void StartMenuItem_Click(object sender, EventArgs e)

        {

            if (StartMenuItem.Text == "开始")

            {

                txtLog.Text += string.Format("{0} {1}{2}", DateTime.Now.ToString("HH:mm:ss"),

                "开始运行...", Environment.NewLine);

                timer.Start();

                StartMenuItem.Text = "结束";

            }

            else

            {

                txtLog.Text += string.Format("{0} {1}{2}", DateTime.Now.ToString("HH:mm:ss"),

                "结束运行...", Environment.NewLine);

                timer.Stop();

                StartMenuItem.Text = "开始";

            }

        }

    }