Code
主要代码如下：

定义委托
        public delegate void ReceiveMessageHandle(string SendPhoneNumber, string SendTime, string SendContent);
        /// <summary>
        /// 接收信息事件
        /// </summary>
        public event ReceiveMessageHandle ReceiveMessageEvent;



formload事件中注册接收事件 

s_port.DataReceived += new SerialDataReceivedEventHandle(s_port_DataReceived);
 s_port.ReceivedBytesThreshold = 1;

//实例化自己定义的委托
ReceiveMessageEvent = new ReceiveMessageHandle(UpdateTextBox);//UpdateTextBox方法是将解码后的内容显示出来



接收事件
   private void s_port_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            try
            {         
                string response = string.Empty;
                response =   s_port.ReadExisting();

                System.Threading.Thread.Sleep(200);
                if (response.Length > 0 && response.IndexOf("+CMT:") != -1)
                {
                    response = response.Replace("\r\n", "|");
                    int i = response.IndexOf("|");
                    if (i == 0)
                        i = 1;
                    else
                        i = 0;
                    i = response.IndexOf("|", i);
                    response = response.Remove(0, i);
                    response = response.Replace("|", "");
                    string SendPhoneNumber = string.Empty;
                    string SendContent = string.Empty;
                    DateTime SendTime = new DateTime();
                    PDUCoding.GSMCode code = new PDUCoding.GSMCode();
                    string SCA = "";
                    //将读出来的PDU串解码,读出来的是“+CMT:15950432221\r\nPDU串”,上面的代码是用remove方法将+CMT:15950432221\r\n去掉，response是发送人的号码加上发送时间加上发送内容的PDU串,下面进行解码,这些都没问题，能正确解码后显示出来
                    if (pduc.DecodingMsg(response, ref SendPhoneNumber, ref SendContent, ref SendTime, ref code, ref SCA))
                    {
                        if (ReceiveMessageEvent != null)
                        {
                            // 通知处理事件
                            this.BeginInvoke(ReceiveMessageEvent, new string[] { SendPhoneNumber.Trim(), SendTime.ToString().Trim(), SendContent.Trim() });
                        }
                    }
                }
            }
            catch (Exception)
            {
                Close();
            }
        }

 

        public void UpdateTextBox(string sendPhoneNumber, string sendTime, string sendContent)
        {
            txtMsg.AppendText("\r\n" + sendPhoneNumber);
            txtMsg.AppendText("\r\n" + sendTime);
            txtMsg.AppendText("\r\n" + sendContent);
        }