简单的串口通讯


请告诉我怎样使用这个方法，第一个参数应该怎么填写
        /// </summary>
        /// <param name="ReadBuf">串口数据缓冲</param>
        /// <param name="ReadRoom">串口数据缓冲空间大小</param>
        /// <param name="ByteTime">字节间隔最大时间</param>
        /// <returns>从串口实际读入的字节个数</returns>
        public int ReadBlock(out byte[] ReadBuf, int ReadRoom, int ByteTime)
        {
            //throw new System.NotImplementedException();
            ReadBuf = new byte[1024];
            Array.Clear(ReadBuf, 0, ReadBuf.Length);            sbyte nBytelen;
            //long nByteRead;            if (serialPort1.IsOpen == false)
                return 0;
            nBytelen = 0;
            serialPort1.ReadTimeout = ByteTime;            while (nBytelen < (ReadRoom - 1))
            {
                try
                {
                    ReadBuf[nBytelen] = (byte)serialPort1.ReadByte();
                    nBytelen++; // add one
                }
                catch (Exception ex)
                {
                    throw new Exception(ex.Message);
                    break;
                }
            }
            ReadBuf[nBytelen] = 0x00;
            return nBytelen;        }