C# 随机数生成避免重复

        public string GetMsgID()
        {
            Random rand = new Random((int)DateTime.Now.Ticks);
            string szRand = rand.Next(0, 9999).ToString().PadLeft(4, '0');
            return string.Format("{0}{1}", DateTime.Now.ToString("yyyyMMddHHmmss"), szRand);
        }

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