[StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
  public struct Head
  {
    public ushort proMagic;     //包起始标记：固定0x7e7e
    public ushort proPackLen;    //包长度：包头 + 数据区 + 包尾长度，注意不要超过最大长度限制
    public long  proSrcAddr;    //源地址：不使用，填0
    public ushort proSrcPort;    //源地址端口:不使用，填0
    public long  proDstAddr;    //目的地址：不使用，填0
    public ushort proDstPort;    //目的端口：不使用，填0
    public ushort proCmdCode;    //命令码：参见以上命令码定义

    public ushort proVersion;    //版本号：不使用，填1
    public char  proSerial;     //报文序号：一条报文实例对应一个序号，不同报文叠加，0-255往复
    public ushort proPackSum;    //总包数：当包长超过最大长度限制时，需要拆包，大包拆小包总数，不拆默认1
    public ushort proPackId;     //当前包号：对应以上总包数的小包标识，不拆默认0

  }

  /// <summary>
  /// 终端信息查询
  /// </summary>
  [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
  public struct PackTerminalSearch5001
  {
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 6)]
    /// <summary>
    /// 终端编号
    /// </summary>
    public string stationCode;

    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)]
    /// <summary>
    /// 回复指令
    /// </summary>
    public Byte[] order;
  }
  /// <summary>
  /// 终端信息数据
  /// </summary>

  [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
  public struct PackTerminalSearch3004
  {
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 6)]
    /// <summary>
    /// 终端编号
    /// </summary>
    public string stationCode;
    /// <summary>
    /// 终端IP
    /// </summary>
    public long terminalIP;
    /// <summary>
    /// 终端端口
    /// </summary>
    public ushort terminalPort;
    /// <summary>
    /// 中心IP
    /// </summary>
    public long serverIP;
    /// <summary>
    /// 测站端口
    /// </summary>
    public ushort serverPort;
    /// <summary>
    /// 磁盘信息数组
    /// </summary>
    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]
    public PackDiskInfo[] diskInfoArray;
  }

  /// <summary>
  /// 磁盘信息
  /// </summary>
  [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
  public struct PackDiskInfo
  {
    /// <summary>
    /// 盘符
    /// </summary>
    public char drive;
    /// <summary>
    /// 总空间
    /// </summary>
    public double totalSize;
    /// <summary>
    /// 可用空间
    /// </summary>
    public double usableSize;
  }

    PackTerminalSearch5001 info;
    info.stationCode = "12345";
    info.order = new byte[6] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05 };
    Byte[] recv = StructToBytes(info);

    object obj = BytesToStuct(recv, typeof(PackTerminalSearch5001));
    PackTerminalSearch5001 info5001 = (PackTerminalSearch5001)obj;
    byte[] order = info5001.order;


    //// <summary>
    /// 结构体转byte数组
    /// </summary>
    /// <param name="structObj">要转换的结构体</param>
    /// <returns>转换后的byte数组</returns>
    public static byte[] StructToBytes(object structObj)
    {
      //得到结构体的大小
      int size = Marshal.SizeOf(structObj);
      //创建byte数组
      byte[] bytes = new byte[size];
      //分配结构体大小的内存空间
      IntPtr structPtr = Marshal.AllocHGlobal(size);
      //将结构体拷到分配好的内存空间
      Marshal.StructureToPtr(structObj, structPtr, false);
      //从内存空间拷到byte数组
      Marshal.Copy(structPtr, bytes, 0, size);
      //释放内存空间
      Marshal.FreeHGlobal(structPtr);
      //返回byte数组
      return bytes;
    }

    /// <summary>
    /// byte数组转结构体
    /// </summary>
    /// <param name="bytes">byte数组</param>
    /// <param name="type">结构体类型</param>
    /// <returns>转换后的结构体</returns>
    public static object BytesToStuct(byte[] bytes, Type type)
    {
      //得到结构体的大小
      int size = Marshal.SizeOf(type);
      //byte数组长度小于结构体的大小
      if (size > bytes.Length)
      {
        //返回空
        return null;
      }
      //分配结构体大小的内存空间
      IntPtr structPtr = Marshal.AllocHGlobal(size);
      //将byte数组拷到分配好的内存空间
      Marshal.Copy(bytes, 0, structPtr, size);
      //将内存空间转换为目标结构体
      object obj = Marshal.PtrToStructure(structPtr, type);
      //释放内存空间
      Marshal.FreeHGlobal(structPtr);
      //返回结构体
      return obj;
    }