字节流和结构体的转换[转]

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Management;

namespace Util
{
    public class NetStreamUtil
    {
        private static byte _fillChar = 0; //the fill character
        
        //convert string to byte array in Ascii with length is len        
        public static byte[] StringToBytes(string str, int len)
        {
            if (string.IsNullOrEmpty(str))
            {
                str = string.Empty;
            }
 
            byte[] result = new byte[len];
            byte[] strBytes = Encoding.Default.GetBytes(str);

            //copy the array converted into result, and fill the remaining bytes with 0
            for (int i = 0; i < len; i++)
                result[i] = ((i < strBytes.Length) ? strBytes[i] : _fillChar);
            
            return result;
        }

        /// <summary>
        /// struct转换为byte[]
        /// </summary>
        /// <param name="structObj">结构体对象</param>
        /// <returns>字节数组</returns>
        public static byte[] StructToBytes(object structObj)
        {
            int size = Marshal.SizeOf(structObj);
            IntPtr buffer = Marshal.AllocHGlobal(size);
            try
            {
                Marshal.StructureToPtr(structObj, buffer, false);
                byte[] bytes = new byte[size];
                Marshal.Copy(buffer, bytes, 0, size);
                return bytes;
            }
            finally
            {
                Marshal.FreeHGlobal(buffer);
            }
        }

       /// <summary>
       ///  byte[]转换为struct
       /// </summary>
       /// <param name="bytes"></param>
       /// <param name="strcutType"></param>
       /// <returns></returns>
       public static object BytesToStruct(byte[] bytes, Type strcutType)   
       {   
             int size = Marshal.SizeOf(strcutType);   
             IntPtr buffer = Marshal.AllocHGlobal(size);   
             try   
             {   
                Marshal.Copy(bytes, 0, buffer, size);   
                return Marshal.PtrToStructure(buffer, strcutType);   
             }   
             finally   
             {   
                Marshal.FreeHGlobal(buffer);   
             }   
        } 

        /// <summary>
        /// IntPtr转换成byte[]
        /// </summary>
        /// <param name="dataBuf"></param>
        /// <param name="length"></param>
        /// <returns></returns>
        public byte[] ConvertToBytes(IntPtr dataBuf, int length)
        {
            byte[] byteBuf = new byte[length];
            Marshal.Copy(dataBuf, byteBuf, 0, length);
            return byteBuf;
        }

        /// <summary>
        /// 获得网卡号
        /// </summary>
        /// <returns></returns>
        public static string GetNetCardMacAddress()
        {
            ManagementClass mc = new ManagementClass("Win32_NetworkAdapterConfiguration");
            ManagementObjectCollection moc = mc.GetInstances();
            string str = "";
            foreach (ManagementObject mo in moc)
            {
                if ((bool)mo["IPEnabled"] == true)
                    str = mo["MacAddress"].ToString();
            }
            return str;
        }
    }
}