[C#]日期處理

常常忘記這些事，寫下來幫助記憶

static DateTime parseDateTime(string datetimestring)
        {
            System.Globalization.CultureInfo ci = new System.Globalization.CultureInfo("zh-TW", true);
            return DateTime.ParseExact(datetimestring, "yyyyMMdd", ci);
        }

 

DateTime d1 = parseDateTime(fromdate);
DateTime d2 = parseDateTime(todate);
TimeSpan delta_day = d1.Subtract(d2);