using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.IO;using System.Runtime.InteropServices;namespace FileSendClient{   [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]  struct StructDemo  {        public byte a;    public byte c;    [MarshalAs(UnmanagedType.ByValArray, SizeConst = 3)]    public byte[] b;    public byte d;    public int e;      }  unsafe class Program  {    static void Main(string[] args)    {      StructDemo sd;      sd.a = 0;      sd.d = 0;      sd.c = 0;      sd.b = new byte[3] { 0, 0, 1 };      sd.e = 5;      int size = 0;      //此處使用非安全代碼來獲取到StructDemo的值      unsafe      {        size = Marshal.SizeOf(sd);      }             byte[] b = StructToBytes(sd,size);       ByteToStruct(b, typeof(StructDemo));     }      //將Byte轉換為結構體類型    public static byte[] StructToBytes(object structObj,int size)    {      StructDemo sd;      int num = 2;      byte[] bytes = new byte[size];      IntPtr structPtr = Marshal.AllocHGlobal(size);      //將結構體拷到分配好的內存空間      Marshal.StructureToPtr(structObj, structPtr, false);      //從內存空間拷貝到byte 數組      Marshal.Copy(structPtr, bytes, 0, size);      //釋放內存空間      Marshal.FreeHGlobal(structPtr);      return bytes;     }     //將Byte轉換為結構體類型    public static object ByteToStruct(byte[] bytes, Type type)    {      int size = Marshal.SizeOf(type);      if (size > bytes.Length)      {        return null;      }      //分配結構體內存空間      IntPtr structPtr = Marshal.AllocHGlobal(size);      //將byte數組拷貝到分配好的內存空間      Marshal.Copy(bytes, 0, structPtr, size);      //將內存空間轉換為目標結構體      object obj = Marshal.PtrToStructure(structPtr, type);      //釋放內存空間      Marshal.FreeHGlobal(structPtr);      return obj;    }  }}