using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Djy.Common { public static class DateTimeExt { private static DateTime dtMin = DateTime.Parse("1970-01-01"); public static string ToSqlServerTimeString(this DateTime dt) { if(dt==dtMin) { return string.Empty; } return dt.ToString("yyyy-MM-dd HH:mm:ss"); } } }