Converting a DateTime to Universal Time Format allows you to avoid local date time format issues when passing DateTime values between systems. Then just use Convert.ToDateTime to convert it back.
Get Current Time In UTC
Use .UtcNow instead of .Now
DateTime TimeNow = new DateTime();
TimeNow = DateTime.UtcNow;
string currentDateTime = TimeNow.ToString("yyyy-MM-ddTHH:mm:ss");
Simpler:
MyString = DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ss")
Convert UTC To Local Format
DateTime dateTime1 = Convert.ToDateTime(MyDateTimeInUtc);
string myDateTime = dateTime1.ToString();
