c# 获取随机数字/字符/时间

using System;
using System.Text;

namespace HuaTong.General.Utility
{
    /// <summary>
    /// 随机字符/数字
    /// </summary>
    public static class Randoms
    {
        static Random rd = new Random();
        static DateTime _minDate = new DateTime(, , );
        static DateTime _maxDate = DateTime.Now.Date;

        /// <summary>
        /// 随机int
        /// </summary>
        /// <returns></returns>
        public static int RandomNumber()
        {
            return RandomNumber(, int.MaxValue);
        }
        /// <summary>
        /// 随机int
        /// </summary>
        /// <returns></returns>
        public static int RandomNumber(int min, int max)
        {
            return rd.Next(min, max);
        }

        /// <summary>
        /// 随机string
        /// </summary>
        /// <returns></returns>
        public static string RandomString(int size, bool isNum = false, int isLower = -)
        {
            StringBuilder builder = new StringBuilder();
            char ch = '';

            for (int i = ; i < size; i++)
            {
                if (isNum)
                {
                    ch = Convert.ToChar(Convert.ToInt32( * rd.NextDouble() + ));
                }
                else
                {
                    if (isLower == -)
                    {
                        int index = Convert.ToInt32(size * rd.NextDouble()) %  ==  ?  : ;
                        ch = Convert.ToChar(Convert.ToInt32( * rd.NextDouble() + index));
                    }
                    else if (isLower == )
                    {
                        ch = Convert.ToChar(Convert.ToInt32( * rd.NextDouble() + ));
                    }
                    else if (isLower > )
                    {
                        ch = Convert.ToChar(Convert.ToInt32( * rd.NextDouble() + ));
                    }
                }
                builder.Append(ch);
            }

            return builder.ToString();
        }

        /// <summary>
        /// 随机datetime
        /// </summary>
        /// <returns></returns>
        public static DateTime RandomDate()
        {
            return RandomDate(_minDate, _maxDate);
        }
        /// <summary>
        /// 随机datetime
        /// </summary>
        /// <returns></returns>
        public static DateTime RandomDate(DateTime minDate, DateTime maxDate)
        {
            int totalDays = (int)((TimeSpan)maxDate.Subtract(minDate)).TotalDays;
            int randomDays = rd.Next(, totalDays);
            return minDate.AddDays(randomDays);
        }

        /// <summary>
        /// 随机bool
        /// </summary>
        /// <returns></returns>
        public static bool RandomBoolean()
        {
            return ((DateTime.Now.Second % ) > );
        }

        /// <summary>
        /// 随机char
        /// </summary>
        /// <returns></returns>
        public static char RandomChar()
        {
            return Convert.ToChar(Convert.ToInt32( * rd.NextDouble() + ));
        }

        /// <summary>
        /// 随机byte
        /// </summary>
        /// <returns></returns>
        public static byte RandomByte()
        {
            return RandomByte(, byte.MaxValue);
        }
        /// <summary>
        /// 随机byte
        /// </summary>
        /// <returns></returns>
        public static byte RandomByte(byte min, byte max)
        {
            return (byte)RandomNumber((int)min, (int)max);
        }

        /// <summary>
        /// 随机shrot
        /// </summary>
        /// <returns></returns>
        public static short RandomShort()
        {
            return RandomShort(, short.MaxValue);
        }
        /// <summary>
        /// 随机short
        /// </summary>

        /// <returns></returns>
        public static short RandomShort(short min, short max)
        {
            return (short)RandomNumber((int)min, (int)max);
        }
    }
}