C# 生成字母验证码

随机生成5位验证码

            Random random = new Random();
            string code = "";
            string letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
            char[] arr=letters.ToCharArray();
            //生成随机的5个
            for(int i = 0; i < 5; i++)
            {
                int k= random.Next(0, 52);
                code +=arr[k];
            }
            return code;