C#生成随机字符串（数字，字母，特殊符号）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            //int number;
            //int count = 7;
            //string checkCode = String.Empty;     //存放随机码的字符串   

            //System.Random random = new Random();

            //for (int i = 0; i < count; i++) //产生7位校验码   
            //{
            //    number = random.Next();
            //    number = number % 36;
            //    if (number < 10)
            //    {
            //        number += 48;    //数字0-9编码在48-57   
            //    }
            //    else
            //    {
            //        number += 55;    //字母A-Z编码在65-90   
            //    }

            //    checkCode += ((char)number).ToString();
            //}
            //Console.WriteLine(checkCode);
            Program p = new Program();
            bool booNumber = true;
            bool booSign = true;
            bool booSmallword = true;
            bool booBigword = true;
            //p.getRandomizer(7, booNumber, booSign, booSmallword, booBigword);
            Console.WriteLine(p.getRandomizer(7, booNumber, booSign, booSmallword, booBigword));
            Console.ReadLine();
        }
        public string getRandomizer(int intLength, bool booNumber, bool booSign, bool booSmallword, bool booBigword)
        {
            //定义
            Random ranA = new Random();
            int intResultRound = 0;
            int intA = 0;
            string strB = "";
            while (intResultRound < intLength)
            {
                //生成随机数A，表示生成类型
                //1=数字，2=符号，3=小写字母，4=大写字母
                intA = ranA.Next(1, 5);
                //如果随机数A=1，则运行生成数字
                //生成随机数A，范围在0-10
                //把随机数A，转成字符
                //生成完，位数+1，字符串累加，结束本次循环
                if (intA == 1 && booNumber)
                {
                    intA = ranA.Next(0, 10);
                    strB = intA.ToString() + strB;
                    intResultRound = intResultRound + 1;
                    continue;
                }
                //如果随机数A=2，则运行生成符号
                //生成随机数A，表示生成值域
                //1：33-47值域，2：58-64值域，3：91-96值域，4：123-126值域
                if (intA == 2 && booSign == true)
                {
                    intA = ranA.Next(1, 5);
                    //如果A=1
                    //生成随机数A，33-47的Ascii码
                    //把随机数A，转成字符
                    //生成完，位数+1，字符串累加，结束本次循环
                    if (intA == 1)
                    {
                        intA = ranA.Next(33, 48);
                        strB = ((char)intA).ToString() + strB;
                        intResultRound = intResultRound + 1;
                        continue;
                    }

                    //如果A=2
                    //生成随机数A，58-64的Ascii码
                    //把随机数A，转成字符
                    //生成完，位数+1，字符串累加，结束本次循环
                    if (intA == 2)
                    {
                        intA = ranA.Next(58, 65);
                        strB = ((char)intA).ToString() + strB;
                        intResultRound = intResultRound + 1;
                        continue;
                    }

                    //如果A=3
                    //生成随机数A，91-96的Ascii码
                    //把随机数A，转成字符
                    //生成完，位数+1，字符串累加，结束本次循环
                    if (intA == 3)
                    {
                        intA = ranA.Next(91, 97);
                        strB = ((char)intA).ToString() + strB;
                        intResultRound = intResultRound + 1;
                        continue;
                    }

                    //如果A=4
                    //生成随机数A，123-126的Ascii码
                    //把随机数A，转成字符
                    //生成完，位数+1，字符串累加，结束本次循环
                    if (intA == 4)
                    {
                        intA = ranA.Next(123, 127);
                        strB = ((char)intA).ToString() + strB;
                        intResultRound = intResultRound + 1;
                        continue;
                    }
                }

                //如果随机数A=3，则运行生成小写字母
                //生成随机数A，范围在97-122
                //把随机数A，转成字符
                //生成完，位数+1，字符串累加，结束本次循环
                if (intA == 3 && booSmallword == true)
                {
                    intA = ranA.Next(97, 123);
                    strB = ((char)intA).ToString() + strB;
                    intResultRound = intResultRound + 1;
                    continue;
                }

                //如果随机数A=4，则运行生成大写字母
                //生成随机数A，范围在65-90
                //把随机数A，转成字符
                //生成完，位数+1，字符串累加，结束本次循环
                if (intA == 4 && booBigword == true)
                {
                    intA = ranA.Next(65, 89);
                    strB = ((char)intA).ToString() + strB;
                    intResultRound = intResultRound + 1;
                    continue;
                }
            }
            return strB;
        }
    }
}