1，yyyyMMdd
DateTime date = DateTime.ParseExact("20190101", "yyyyMMdd", System.Globalization.CultureInfo.CurrentCulture);
2，ddMMyyyy
DateTime date = DateTime.ParseExact("15/04/2019", "dd/MM/yyyy", System.Globalization.CultureInfo.GetCultureInfo("en-US"));
原文：https://www.cnblogs.com/footmark/p/10764010.html