سلام شايد اين كمك كنه
DateTime d1 = newDateTime();
DateTime d2 = newDateTime();
DateTime result = newDateTime();
//Different Times
d1 =DateTime.Now;
d2 = DateTime.Now.AddHours(1);
d2 = DateTime.Now.AddMinutes(5);
//SUB
result = d1.AddSeconds((double)(d2.Second));
result = result.AddMinutes((double)(d2.Minute));
result = result.AddHours((double)(d2.Hour));