The best way (I think) is to store Date/Time in database as a Date/Time type column.
When you then retrieve the Date/Time from the database and what to display it for the user. Then you can do DateTime.ToString(...).
Always save you Date/Time in a DateTime class, and when it is time to display it in UI to the user, then convert it.
Do not convert back and forth.
But if you have to save a Date/Time to a string and save it to a database. Then call
DateTime.ToString("s")
The Sortable ("s") Format Specifier[
^]
dtpStart.Value = (clsGlobal.Configuration.ScheduleEveryStart == "") ? System.DateTime.Now : DateTime.ParseExact(clsGlobal.Configuration.ScheduleEveryStart, "s", CultureInfo.InvariantCulture);