c# udp通信中用结构体序列化后报文大小取不到，请教
发送接收代码：
private void SendData() { UdpClient MyUdpClient = new UdpClient(); IPAddress remoteIp; if (IPAddress.TryParse(txt_RemotIp.Text.Trim(),out remoteIp) == false) { MessageBox.Show("错误", "远程ip地址格式不对"); return; } IPEndPoint iep = new IPEndPoint(remoteIp, port); byte[] bytes = proData(); try { MyUdpClient.Send(bytes, bytes.Length,iep); MyUdpClient.Close(); } catch (Exception ex) { LogHelper.WriteError("SendData_catch", ex.Message); MessageBox.Show("发送失败","错误"); } finally { MyUdpClient.Close(); } } private void ReceiveDate() { udpClient = new UdpClient(port); IPEndPoint remote = null; while (true) { try { byte[] bytes = udpClient.Receive(ref remote); UnPackUdp_data(bytes); } catch (Exception ex) { LogHelper.WriteError("ReceiveDate_catch", ex.Message); break; } } } private UDP_data Data(int packIndex,int type) { byte[] btmp=Encoding.UTF8.GetBytes(txt_SendMsg.Text.Trim()); UDP_data sd = new UDP_data(); sd.packIndex = packIndex; sd.type = type; sd.data = btmp; sd.length = btmp.Length; return sd; } private void UnPackUdp_data(byte[] bytes) { string str = "报文大小：" + bytes.Length.ToString(); UDP_data rd = new UDP_data(); rd = (UDP_data)BytesToStruts(bytes, typeof(UDP_data)); str = str + "，包序号：" + rd.packIndex.ToString(); str = str + "，包类型：" + rd.type.ToString(); str = str + "，数据体长：" + rd.length.ToString(); str = str + "，内容：" + Encoding.UTF8.GetString(rd.data); AddListReceive(str); LogHelper.WriteInfo("", str); LogHelper.WriteInfo("", BitConverter.ToString(bytes)); } private byte[] proData() { // return Pack(1, 1, Encoding.UTF8.GetBytes(txt_SendMsg.Text.Trim())); return StrutsToBytesArray(Data(0,1)); }public struct UDP_data { public int packIndex;//包序号 public int type;//数据类型 public int length;//数据长度 public byte[] data;//数据体 //public byte crc; } /// <summary> /// 结构体到byte[] /// </summary> /// <param name="structObj"></param> /// <returns></returns> public static byte[] StrutsToBytesArray(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[]到结构体 /// </summary> /// <param name="bytes"></param> /// <param name="type"></param> /// <returns></returns> public static object BytesToStruts(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; }