public static long DateDiff(DateInterval interval, DateTime dt1, DateTime dt2, DayOfWeek eFirstDayOfWeek)
{
long month;
if (interval == DateInterval.Year)
{
month = (long)(dt2.Year - dt1.Year);
}
else if (interval != DateInterval.Month)
{
TimeSpan timeSpan = dt2 - dt1;
if ((interval == DateInterval.Day ? true : interval == DateInterval.DayOfYear))
{
month = DateAndTime.Round(timeSpan.TotalDays);
}
else if (interval == DateInterval.Hour)
{
month = DateAndTime.Round(timeSpan.TotalHours);
}
else if (interval == DateInterval.Minute)
{
month = DateAndTime.Round(timeSpan.TotalMinutes);
}
else if (interval == DateInterval.Second)
{
month = DateAndTime.Round(timeSpan.TotalSeconds);
}
else if (interval == DateInterval.Weekday)
{
month = DateAndTime.Round(timeSpan.TotalDays / 7);
}
else if (interval == DateInterval.WeekOfYear)
{
while (dt2.DayOfWeek != eFirstDayOfWeek)
{
dt2 = dt2.AddDays(-1);
}
while (dt1.DayOfWeek != eFirstDayOfWeek)
{
dt1 = dt1.AddDays(-1);
}
timeSpan = dt2 - dt1;
month = DateAndTime.Round(timeSpan.TotalDays / 7);
}
else if (interval == DateInterval.Quarter)
{
double quarter = (double)DateAndTime.GetQuarter(dt1.Month);
double num = (double)DateAndTime.GetQuarter(dt2.Month);
double num1 = num - quarter;
double year = (double)(4 * (dt2.Year - dt1.Year));
month = DateAndTime.Round(num1 + year);
}
else
{
month = (long)0;
}
}
else
{
month = (long)(dt2.Month - dt1.Month + 12 * (dt2.Year - dt1.Year));
}
return(month);
}
public static long DateDiff(DateInterval interval, DateTime dt1, DateTime dt2)
{
long num = DateAndTime.DateDiff(interval, dt1, dt2, DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek);
return(num);
}
