using System;using System.Runtime.InteropServices;using System.IO;namespace tx{    struct ST    {       public byte c1;       public float x;       public int y;    }    class Ct    {        [DllImport("msvcrt.dll", EntryPoint = "memcpy", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]        public static extern void MemCopy(byte[] dest, byte[] src, int count);//字节数组到字节数组的拷贝        [DllImport("msvcrt.dll", EntryPoint = "memcpy", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]        public static extern void MemCopy(int[] dest, byte[] src, int count);//字节数组到整形数组的拷贝        [DllImport("msvcrt.dll", EntryPoint = "memcpy", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]        public unsafe static extern void MemCopy(ref ST dest, byte[] src, int count);//注意只有结构体能这么做,class不可以        [DllImport("msvcrt.dll", EntryPoint = "memcpy", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]        public static extern void MemCopy(ref byte dest, ref byte src, int count);//字节数组到整形数组的拷贝        static void Main(string[] args)        {            //测试----------------------------------------------            var ms = new MemoryStream();            BinaryWriter writer = new BinaryWriter(ms);            writer.Write((byte)'a');            writer.Write((byte)'b');            writer.Write((byte)'c');            writer.Write((byte)'d');            writer.Write(10.2f);            writer.Write((Int32)30); writer.Write((byte)'w');            writer.Write((byte)'b');            writer.Write((byte)'c');            writer.Write((byte)'d');            writer.Write((float)799);            writer.Write((Int32)242);            var len = ms.Length;            int[] bs = new int[len/4];            byte[] bss = new byte[len];            byte[] buf = ms.GetBuffer();            var ot = new ST();            ST[] aot = new ST[2];            Buffer.BlockCopy(buf, 0, bs, 0, (int)ms.Length);            //Buffer.BlockCopy(buf, 0, aot, 0, (int)ms.Length);//错误，blockcopy只能用于基元数组            MemCopy(bss, buf, (int)len);            MemCopy(ref ot, buf, (int)len/2);//注意只有结构体能这么做,class不可以            MemCopy(ref aot[0], buf, (int)len);            byte[] sub = new byte[4];        }    }}