private void Form1_Load(object sender, EventArgs e)

        {

            serialPort1.PortName = "COM1";

            serialPort1.BaudRate = 9600;

            serialPort1.Parity = Parity.None;

            serialPort1.DataBits = 8;

            serialPort1.StopBits = StopBits.One;

            serialPort1.Open();

            serialPort1.ReceivedBytesThreshold = 1;

            serialPort1.DataReceived += new SerialDataReceivedEventHandler(serialPort1_DataReceived);         

        }

        private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)

        {

            this.label1.Text =serialPort1.ReadLine();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            if (serialPort1.IsOpen)

            {

                label1.Text = "打开";

            }

            else

            {

                label1.Text = "guanbi";

            }

        }

        private void serialPort1_PinChanged(object sender, SerialPinChangedEventArgs e)

        {

        }

    }

}