c#随机生成汉字、字母、数字

　　　　 /// <summary>
        /// 替换变量
        /// </summary>
        /// <param name="content"></param>
        /// <returns></returns>
        public static string replaceBianLiang(string content)
        {
            content = content.Replace("{当前时间}", DateTime.Now.TimeOfDay.ToString());
            string[] bianliang = new string[] { "{随机字母}", "{随机数字}", "{随机汉字}" };
            Regex r;
            int count;
            string readstr = "";
            foreach (string str in bianliang)
            {
                count = (content.Length - content.Replace(str, "").Length) / str.Length;
                if (str == "{随机汉字}") readstr = RandChina(count);
                if (str == "{随机数字}") readstr = GenerateCheckCodeNum(count);
                if (str == "{随机字母}") readstr = GenerateRandomLetter(count);
                if (count > readstr.Length) count = readstr.Length;
                r = new Regex(str.Replace("{", "\\{").Replace("}", "\\}"));
                for (int i = 0; i < count; i++)
                {
                    content = r.Replace(content, readstr.Substring(i, 1), 1);
                }
            }
            return content;
        }


        /// <summary>
        /// 随机生成字母
        /// </summary>
        /// <param name="Length"></param>
        /// <returns></returns>
        public static string GenerateRandomLetter(int Length)
        {
            char[] Pattern = new char[] { \'A\', \'B\', \'C\', \'D\', \'E\', \'F\', \'G\', \'H\', \'I\', \'J\', \'K\', \'L\', \'M\', \'N\', \'O\', \'P\', \'Q\', \'R\', \'S\', \'T\', \'U\', \'V\', \'W\', \'X\', \'Y\', \'Z\', \'a\', \'b\', \'c\', \'d\', \'e\', \'f\', \'g\', \'h\', \'i\', \'j\', \'k\', \'l\', \'m\', \'n\', \'o\', \'p\', \'q\', \'r\', \'s\', \'t\', \'u\', \'v\', \'w\', \'x\', \'y\', \'z\' };
            string result = "";
            int n = Pattern.Length;
            Random random = new Random(~unchecked((int)DateTime.Now.Ticks));
            for (int i = 0; i < Length; i++)
            {
                int rnd = random.Next(0, n);
                result += Pattern[rnd];
            }
            return result;
        }

        /// <summary>
        /// 随机生成数字
        /// </summary>
        /// <param name="codeCount"></param>
        /// <returns></returns>
        public static string GenerateCheckCodeNum(int codeCount)
        {
            int rep = 0;
            string str = string.Empty;
            long num2 = DateTime.Now.Ticks + rep;
            rep++;
            Random random = new Random(((int)(((ulong)num2) & 0xffffffffL)) | ((int)(num2 >> rep)));
            for (int i = 0; i < codeCount; i++)
            {
                int num = random.Next();
                str = str + ((char)(0x30 + ((ushort)(num % 10)))).ToString();
            }
            return str;
        }

        /// <summary>
        /// 此函数为生成指定数目的汉字
        /// </summary>
        /// <param name="charLen">汉字数目</param>
        /// <returns>所有汉字</returns>
        public static string RandChina(int charLen)
        {
            int area, code;//汉字由区位和码位组成(都为0-94,其中区位16-55为一级汉字区,56-87为二级汉字区,1-9为特殊字符区)
            StringBuilder strtem = new StringBuilder();
            Random rand = new Random();
            for (int i = 0; i < charLen; i++)
            {
                area = rand.Next(16, 88);
                if (area == 55)//第55区只有89个字符
                {
                    code = rand.Next(1, 90);
                }
                else
                {
                    code = rand.Next(1, 94);
                }
                strtem.Append(Encoding.GetEncoding("GB2312").GetString(new byte[] { Convert.ToByte(area + 160), Convert.ToByte(code + 160) }));
            }
            return strtem.ToString();
        }