简单来讲就是先生成字符串的md5，然后再用md5的前几位转换为Int作为随机种子

废话不多说直接贴代码：

using System;
using System.Collections.Generic;
using System.Security.Cryptography;
using System.Text;

namespace Kakkk
{
    class Program
    {
        static void Main(string[] args)
        {
            string str = "emmmmm";
            Random random = new Random(GetSeedFromString(str));
            Console.WriteLine(random.Next());
        }

        //获取随机种子
        public static int GetSeedFromString(string value)
        {
            using (var md5 = MD5.Create())
            {
                var inputBytes = Encoding.UTF8.GetBytes(value);
                byte[] hashBytes = md5.ComputeHash(inputBytes);
                return BitConverter.ToInt32(hashBytes, 0);
            }
        }
    }
}