Try this code
DateTime myDate = DateTime.ParseExact("1389/11/01", "yyyy/MM/dd", System.Globalization.CultureInfo.InvariantCulture)
DateTime myDate = DateTime.ParseExact("1389/11/01", "yyyy/MM/dd", System.Globalization.CultureInfo.InvariantCulture, DateTimeStyles.None)
And save myDate to database