C#中string与byte[]的转换帮助类

/*
* @author wuerping
* @version 1.0
* @date 2004/11/30
* @description:
*/
using System;
using System.Text;
namespace sidlehelper
{
    /// <summary>
    /// summary description for strhelper.
    /// 命名缩写：
    /// str: unicode string
    /// arr: unicode array
    /// hex: 二进制数据
    /// hexbin: 二进制数据用ascii字符表示 例 字符1的hex是0x31表示为hexbin是 31
    /// asc: ascii
    /// uni: unicode
    /// </summary>
    public sealed class strhelper
    {
        #region hex与hexbin的转换
        public static void hexbin2hex(byte[] bhexbin, byte[] bhex, int nlen)
        {
            for (int i = 0; i < nlen / 2; i++)
            {
                if (bhexbin[2 * i] < 0x41)
                {
                    bhex[i] = Convert.ToByte(((bhexbin[2 * i] - 0x30) << 4) & 0xf0);
                }
                else
                {
                    bhex[i] = Convert.ToByte(((bhexbin[2 * i] - 0x37) << 4) & 0xf0);
                }

                if (bhexbin[2 * i + 1] < 0x41)
                {
                    bhex[i] |= Convert.ToByte((bhexbin[2 * i + 1] - 0x30) & 0x0f);
                }
                else
                {
                    bhex[i] |= Convert.ToByte((bhexbin[2 * i + 1] - 0x37) & 0x0f);
                }
            }
        }
        public static byte[] hexbin2hex(byte[] bhexbin, int nlen)
        {
            if (nlen % 2 != 0)
                return null;
            byte[] bhex = new byte[nlen / 2];
            hexbin2hex(bhexbin, bhex, nlen);
            return bhex;
        }
        public static void hex2hexbin(byte[] bhex, byte[] bhexbin, int nlen)
        {
            byte c;
            for (int i = 0; i < nlen; i++)
            {
                c = Convert.ToByte((bhex[i] >> 4) & 0x0f);
                if (c < 0x0a)
                {
                    bhexbin[2 * i] = Convert.ToByte(c + 0x30);
                }
                else
                {
                    bhexbin[2 * i] = Convert.ToByte(c + 0x37);
                }
                c = Convert.ToByte(bhex[i] & 0x0f);
                if (c < 0x0a)
                {
                    bhexbin[2 * i + 1] = Convert.ToByte(c + 0x30);
                }
                else
                {
                    bhexbin[2 * i + 1] = Convert.ToByte(c + 0x37);
                }
            }
        }
        public static byte[] hex2hexbin(byte[] bhex, int nlen)
        {
            byte[] bhexbin = new byte[nlen * 2];
            hex2hexbin(bhex, bhexbin, nlen);
            return bhexbin;
        }
        #endregion

        #region 数组和字符串之间的转化
        public static byte[] str2arr(string s)
        {
            return (new UnicodeEncoding()).GetBytes(s);
        }
        public static string arr2str(byte[] buffer)
        {
            return (new UnicodeEncoding()).GetString(buffer, 0, buffer.Length);
        }

        public static byte[] str2ascarr(string s)
        {
            return System.Text.UnicodeEncoding.Convert(System.Text.Encoding.Unicode,
            System.Text.Encoding.ASCII,
            str2arr(s));
        }

        public static byte[] str2hexascarr(string s)
        {
            byte[] hex = str2ascarr(s);
            byte[] hexbin = hex2hexbin(hex, hex.Length);
            return hexbin;
        }
        public static string ascarr2str(byte[] b)
        {
            return System.Text.UnicodeEncoding.Unicode.GetString(
            System.Text.ASCIIEncoding.Convert(System.Text.Encoding.ASCII,
            System.Text.Encoding.Unicode,
            b)
            );
        }

        public static string hexascarr2str(byte[] buffer)
        {
            byte[] b = hex2hexbin(buffer, buffer.Length);
            return ascarr2str(b);
        }
        #endregion
    }
}