c#获取当前系统时间，并提取按格式提取年月日为字符串

class Program
    {
        static void Main(String[] args)
        {
            DateTime currentTime = System.DateTime.Now;
            string defaultYear = currentTime.Year.ToString("d4");
            string defaultMonth = currentTime.Month.ToString("d2");//例：“06”
            //string defaultDay = currentTime.Day.ToString("d2");
            //string defaultHour = currentTime.Hour.ToString("d2");
            string defaultDay = currentTime.AddHours(-24).Day.ToString("d2");
            string dateString1 = defaultYear + defaultMonth + defaultDay + "08";
            DateTime dt1 = DateTime.ParseExact(dateString1,"yyyyMMddHH",System.Globalization.CultureInfo.CurrentCulture);
            dateTimePicker1.Value = dt1;
            
        }
    }