using System;

namespace DS.WMS.PrintApi.Utils
{
    public class NumUtil
    {
        #region 生成随机推荐码

        /// <summary>
        /// 生成随机数的种子
        /// </summary>
        /// <returns></returns>
        private static int getNewSeed()
        {
            byte[] rndBytes = new byte[4];
            System.Security.Cryptography.RNGCryptoServiceProvider rng =
                new System.Security.Cryptography.RNGCryptoServiceProvider();
            rng.GetBytes(rndBytes);
            return BitConverter.ToInt32(rndBytes, 0);
        }

        #endregion 生成随机推荐码
        /// <summary>
        /// 生成随机数
        /// </summary>
        /// <param name="length">位数</param>
        /// <returns></returns>
        public static string GetRandomString(int len)
        {
            string s = "123456789abcdefghijklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";
            string reValue = string.Empty;
            Random rnd = new Random(getNewSeed());
            while (reValue.Length < len)
            {
                string s1 = s[rnd.Next(0, s.Length)].ToString();
                if (reValue.IndexOf(s1) == -1) reValue += s1;
            }

            return reValue;
        }
    }
}