C# 批量生成随机数(可实现2秒生成100万不重复数据)

【实例截图】

【核心代码】

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Collections;
using System.Diagnostics;
using System.IO;

namespace WindowsFormsApplication1
{
	public partial class 系统唯一数 : Form
	{
		public 系统唯一数()
		{
			InitializeComponent();
		}

		private void btnCreate_Click(object sender, EventArgs e)
		{
            this.UseWaitCursor = true;
			Stopwatch sw = new Stopwatch();
			sw.Start();
			List<string> list = GetRandString((int)numLen.Value, (int)numCount.Value);
            sw.Stop();
            this.UseWaitCursor = false;
			if (list == null)
			{
				return;
			}

			string strInfo = string.Format("成功生成{1}个随机字符串！用时：{0}毫秒！", sw.ElapsedMilliseconds, numCount.Value);
			strInfo  = "\r\n"   "是否查看生成结果？";

			DialogResult result = MessageBox.Show(strInfo, "提示", MessageBoxButtons.OKCancel, MessageBoxIcon.Information);
			if (result == DialogResult.OK)
			{
				StringBuilder str_content = new StringBuilder();
				foreach (string r in list)
				{
					str_content.Append(r   "\r\n");
				}

				string file_path = Application.StartupPath   "\\rand_"   DateTime.Now.ToFileTime().ToString()   ".txt";
				File.WriteAllText(file_path, str_content.ToString());
				Process.Start(file_path);
			}
		}

        /// <summary>
        /// 随机排序
        /// </summary>
        /// <param name="charList"></param>
        /// <returns></returns>
		private List<string> SortByRandom(List<string> charList)
		{
			Random rand = new Random();
			for (int i = 0; i < charList.Count; i  )
			{
				int index = rand.Next(0, charList.Count);
				string temp = charList[i];
				charList[i] = charList[index];
				charList[index] = temp;
			}

			return charList;
		}

		private void ShowError(string strError)
		{
			MessageBox.Show(strError, "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
		}

        /// <summary>
        /// 获取随机字符串
        /// </summary>
        /// <param name="len"></param>
        /// <param name="count"></param>
        /// <returns></returns>
		private List<string> GetRandString(int len, int count)
		{
			double max_value = Math.Pow(36, len);
			if (max_value > long.MaxValue)
			{
				ShowError(string.Format("Math.Pow(36, {0}) 超出 long最大值！", len));
				return null;
			}
			
			long all_count = (long)max_value;
			long stepLong = all_count / count;
			if (stepLong > int.MaxValue)
			{
				ShowError(string.Format("stepLong ({0}) 超出 int最大值！", stepLong));
				return null;
			}
			int step = (int)stepLong;
			if (step < 3)
			{
				ShowError("step 不能小于 3!");
				return null;
			}
			long begin = 0;
			List<string> list = new List<string>();
			Random rand = new Random();
			while (true)
			{
				long value = rand.Next(1, step)   begin;
				begin  = step;
				list.Add(GetChart(len, value));
				if (list.Count == count)
				{
					break;
				}
			}

			list = SortByRandom(list);

			return list;
		}

        //数字 字母
		private const string CHAR = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

        /// <summary>
        /// 将数字转化成字符串
        /// </summary>
        /// <param name="len"></param>
        /// <param name="value"></param>
        /// <returns></returns>
		private string GetChart(int len, long value)
		{
			StringBuilder str = new StringBuilder();
			while (true)
			{
				str.Append(CHAR[(int)(value % 36)]);
				value = value / 36;
				if (str.Length == len)
				{
					break;
				}
			}

			return str.ToString();
		}
	}
}