public void serialPort_ReceiveData(object sender, SerialDataReceivedEventArgs e)
        {
            string s = ""; 
            byte[] APIcmd = new byte[34];
            this.serialPort1.Read(APIcmd, 0, APIcmd.Length);

            s = System.Text.ASCIIEncoding.ASCII.GetString(APIcmd);//这样处理得到的结果是s="123\0\0\0\0\0\0\0\0\0\0"
            //for (int i = 0; i < APIcmd.Length; i++)
            //{
            //    s += APIcmd[i].ToString();
            //}//这样处理的结果是s="495051000000000000"
            this.textBox1.Invoke(new testTextBox(stringTest), new object[] { s.Trim() });
        }