Asp.NET 生成随机码基类(随机字母,随机数字,随机字母+数字 )

using  System;
using  System.Data;
using  System.Configuration;
using  System.Web;
using  System.Web.Security;
using  System.Web.UI;
using  System.Web.UI.WebControls;
using  System.Web.UI.WebControls.WebParts;
using  System.Web.UI.HtmlControls;
using  System.Text;


namespace  EC
... {
    /**//// <summary>
    /// 随机函数
    /// </summary>
    public class RandomObject
    ...{

        数字随机数#region 数字随机数
        /**//// <summary>
        /// 数字随机数
        /// </summary>
        /// <param name="n">生成长度</param>
        /// <returns></returns>
        public static string RandNum(int n)
        ...{
            char[] arrChar = new char[] ...{ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
            StringBuilder num = new StringBuilder();

            Random rnd = new Random(DateTime.Now.Millisecond);

            for (int i = 0; i < n; i++)
            ...{
                num.Append(arrChar[rnd.Next(0, 9)].ToString());

            }

            return num.ToString();
        }
        #endregion

        数字和字母随机数#region 数字和字母随机数
        /**//// <summary>
        /// 数字和字母随机数
        /// </summary>
        /// <param name="n">生成长度</param>
        /// <returns></returns>
        public static string RandCode(int n)
        ...{
            char[] arrChar = new char[]...{
           'a','b','d','c','e','f','g','h','i','j','k','l','m','n','p','r','q','s','t','u','v','w','z','y','x',
           '0','1','2','3','4','5','6','7','8','9',
           'A','B','C','D','E','F','G','H','I','J','K','L','M','N','Q','P','R','T','S','V','U','W','X','Y','Z'
          };

            StringBuilder num = new StringBuilder();

            Random rnd = new Random(DateTime.Now.Millisecond);
            for (int i = 0; i < n; i++)
            ...{
                num.Append(arrChar[rnd.Next(0, arrChar.Length)].ToString());

            }

            return num.ToString();
        }
        #endregion

        字母随机数#region 字母随机数
        /**//// <summary>
        /// 字母随机数
        /// </summary>
        /// <param name="n">生成长度</param>
        /// <returns></returns>
        public static string RandLetter(int n)
        ...{
            char[] arrChar = new char[]...{
            'a','b','d','c','e','f','g','h','i','j','k','l','m','n','p','r','q','s','t','u','v','w','z','y','x',
            '_',
           'A','B','C','D','E','F','G','H','I','J','K','L','M','N','Q','P','R','T','S','V','U','W','X','Y','Z'
          };

            StringBuilder num = new StringBuilder();

            Random rnd = new Random(DateTime.Now.Millisecond);
            for (int i = 0; i < n; i++)
            ...{
                num.Append(arrChar[rnd.Next(0, arrChar.Length)].ToString());

            }

            return num.ToString();
        }
        #endregion

        日期随机函数#region 日期随机函数
        /**//// <summary>
        /// 日期随机函数
        /// </summary>
        /// <param name="ra">长度</param>
        /// <returns></returns>
        public static string DateRndName(Random ra)
        ...{
            DateTime d = DateTime.Now;
            string s = null, y, m, dd, h, mm, ss;
            y = d.Year.ToString();
            m = d.Month.ToString();
            if (m.Length < 2) m = "0" + m;
            dd = d.Day.ToString();
            if (dd.Length < 2) dd = "0" + dd;
            h = d.Hour.ToString();
            if (h.Length < 2) h = "0" + h;
            mm = d.Minute.ToString();
            if (mm.Length < 2) mm = "0" + mm;
            ss = d.Second.ToString();
            if (ss.Length < 2) ss = "0" + ss;
            s += y + m + dd + h + mm + ss;
            s += ra.Next(100, 999).ToString();
            return s;
        }
        #endregion

        生成GUID#region 生成GUID
        /**//// <summary>
        /// 生成GUID
        /// </summary>
        /// <returns></returns>
        public static string GetGuid()
        ...{
            System.Guid g = System.Guid.NewGuid();
            return g.ToString();
        }
        #endregion
    }
}