/// <summary> /// Compares a Date to another and returns a <c>DateTimeSpan</c>. /// </summary> /// <param name="dateStart">The date start.</param> /// <param name="dateEnd">The date end.</param> /// <returns>A DateTimeSpan with the Years, Months, Days, Hours, Minutes, Seconds and Milliseconds between the dates.</returns> public static DateTimeSpan GetDateTimeSpan(this DateTime dateStart, DateTime dateEnd) => DateTimeSpan.CompareDates(dateStart, dateEnd);
internal static DateTimeSpan CompareDates(DateTime date1, DateTime date2)
{
if (date2 < date1)
{
var sub = date1;
date1 = date2;
date2 = sub;
}
var current = date1;
var years = 0;
var months = 0;
var days = 0;
var phase = Phase.Years;
var span = new DateTimeSpan();
var officialDay = current.Day;
while (phase != Phase.Done)
{
switch (phase)
{
case Phase.Years:
if (current.AddYears(years + 1) > date2)
{
phase = Phase.Months;
current = current.AddYears(years);
}
else
{
years++;
}
break;
case Phase.Months:
if (current.AddMonths(months + 1) > date2)
{
phase = Phase.Days;
current = current.AddMonths(months);
if (current.Day < officialDay &&
officialDay <= DateTime.DaysInMonth(current.Year, current.Month))
{
current = current.AddDays(officialDay - current.Day);
}
}
else
{
months++;
}
break;
case Phase.Days:
if (current.AddDays(days + 1) > date2)
{
current = current.AddDays(days);
var timespan = date2 - current;
span = new DateTimeSpan(
years,
months,
days,
timespan.Hours,
timespan.Minutes,
timespan.Seconds,
timespan.Milliseconds);
phase = Phase.Done;
}
else
{
days++;
}
break;
}
}
return(span);
}