关于串口接收数据不全的问题

/// <summary>
    /// 字节缓冲器
    /// </summary>
    public class ByteQueue
    {
        private List<byte> m_buffer = new List<byte>();
        public bool Find()
        {
            if (m_buffer.Count == 0)
                return false;
            int HeadIndex = m_buffer.FindIndex(o => o == 0xAA);
 
            if (HeadIndex == -1)
            {
                m_buffer.Clear();
                return false; //没找到AA
            }
 
            else if (HeadIndex != 0) //不为开头移掉之前的字节
            {
                if (HeadIndex > 1)
                    m_buffer.RemoveRange(0, HeadIndex);
            }
 
            int length= GetLength();
 
            if (m_buffer.Count <length)
            {
                return false;
            }
 
            int TailIndex = m_buffer.FindIndex(o => o == 0x55); //查找55的位置
 
            if (TailIndex == -1)
            {
                //这一步为防止连发一个AA开头的包后，没发55，而又发了一个AA
                int head = m_buffer.FindLastIndex(o => o == 0xAA);
                if (head > -1)
                {
                    m_buffer.RemoveRange(0, head);
                }
                return false;
            }
            else if (TailIndex + 1 != length) //计算包尾是否与包长度相等
            {
                m_buffer.RemoveRange(0, TailIndex);
                return false;
            }
 
            return true;
        }
 
        /// <summary>
        /// 命令类型
        /// </summary>
        /// <returns></returns>
        public byte Cmd()
        {
            if (m_buffer.Count >= 2)
            {
                return m_buffer[1];
            }
            return 0;
        }
 
        /// <summary>
        /// 序号
        /// </summary>
        /// <returns></returns>
        public byte Number()
        {
            if (m_buffer.Count >= 3)
            {
                return m_buffer[2];
            }
            return 0;
        }
 
        /// <summary>
        /// 包长度
        /// </summary>
        /// <returns></returns>
        public int GetLength()
        {
            int len = 5;//AA 命令类型 序号 校验和 55
            if (m_buffer.Count >= 3)
            {
                switch (m_buffer[2]) //第三字节为序号
                { 
                    case 0x00: //序号
                        return len + 16;
                    case 0x01: //序号
                        return len + 10;
                    case 0x02: //序号
                        return len + 12;
                }
            }
            return 0;
        }
        /// <summary>
        /// 提取数据
        /// </summary>
        public void Dequeue(byte[] buffer, int offset,int size)
        {
            m_buffer.CopyTo(0,buffer,offset,size);
            m_buffer.RemoveRange(0, size);
        }
 
        /// <summary>
        /// 队列数据
        /// </summary>
        /// <param name="buffer"></param>
        public void Enqueue(byte[] buffer)
        {
            m_buffer.AddRange(buffer);
        }
    }

private ByteQueue queue = new ByteQueue();
 private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            int len = serialPort1.BytesToRead;
            if (len > 0)
            {
                byte[] temp = new byte[len];
                serialPort1.Read(temp, 0, len);
                queue.Enqueue(temp);
                while (queue.Find()) //while可处理同时接收到多个AA ... 55 ,AA...55的包
                {
                    int length = queue.GetLength();
                    byte[] readBuffer = new byte[len];
                    queue.Dequeue(readBuffer, 0, length);
                    OnReceiveData(readBuffer); //<这里自己写一个委托吧就OK了
                }
 
            }
 
        }

private List<byte> buffer = new List<byte>(4096);
private void sp_DataReceived(objectsender, EventArgs e) //sp是串口控件
{
int n = sp.BytesToRead;
byte[] buf = new byte[n];
sp.Read(buf, 0, n);

//1.缓存数据
buffer.AddRange(buf);
//2.完整性判断
while (buffer.Count >= 4) //至少包含帧头（2字节）、长度（1字节）、校验位（1字节）；根据设计不同而不同
{
//2.1 查找数据头
if (buffer[0] == 0x01) //传输数据有帧头，用于判断
{
int len = buffer[2];
if (buffer.Count < len + 4) //数据区尚未接收完整
{
break;
}
//得到完整的数据，复制到ReceiveBytes中进行校验
buffer.CopyTo(0, ReceiveBytes, 0, len + 4);
byte jiaoyan; //开始校验
jiaoyan = this.JY(ReceiveBytes);
if (jiaoyan != ReceiveBytes[len+3]) //校验失败，最后一个字节是校验位
{
buffer.RemoveRange(0, len + 4);
MessageBox.Show("数据包不正确！");
continue;
}
buffer.RemoveRange(0, len + 4);
/////执行其他代码，对数据进行处理。
}
else //帧头不正确时，记得清除
{
buffer.RemoveAt(0);
}
}
}