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Find next 5 working days starting from today

I use nager.date to know if a day is a holiday day or a weekend day Saturday and Sunday).
I need to extract the date (starting from today or any other date) after 5 working days.
DateTime date1 = new DateTime(2019, 12, 23);
int i = 0;
while ( i < 5)
{
if (DateSystem.IsPublicHoliday(date1, CountryCode.IT) || DateSystem.IsWeekend(date1, CountryCode.IT))
{
date1 = date1.AddDays(1);
}
else
{
date1= date1.AddDays(1);
i++;
}
}
The problem of this code is that if the last else occurs, it add me 1 day but without doing any other check.
For example:
If the start date is 13/07/2020, the result will be at the end 18/07/2020 and as you can see is on Saturday.
How could I modify this code to achieve what I need?

The order is important. The AddDays should be called first, and after it is called we check if the new day matches our criteria.
Note: I have renamed the i variable so it is more clear.
DateTime date1 = new DateTime(2019, 12, 23);
int daysAdded = 0;
while (daysAdded < 5)
{
date1 = date1.AddDays(1);
if (!DateSystem.IsPublicHoliday(date1, CountryCode.IT) && !DateSystem.IsWeekend(date1, CountryCode.IT)) {
// We only consider laboral days
// laboral days: They are not holidays and are not weekends
daysAdded ++;
}
}

I always try to generalize my solutions, so here's one enabling LINQ:
public bool IsWorkingDay(DateTime dt)
=> !DateSystem.IsPublicHoliday(dt) && !DateSystem.IsWeekend(dt);
public DateTime NextWorkingDay(DateTime dt)
{
dt = dt.AddDays(1);
while (!IsWorkingDay(dt))
dt = dt.AddDays(1);
return dt;
}
public IEnumerable<DateTime> WorkingDaysFrom(DateTime dt)
{
if (!IsWorkingDay(dt))
dt = NextWorkingDay(dt); // includes initial dt, remove if unwanted
while (true)
{
yield return dt;
dt = NextWorkingDay(dt);
}
}
This will pump out working days from a given date until end of time, and then use LINQ to grab the number you want:
var next5 = WorkingDaysFrom(DateTime.Today).Take(5).ToList();
here's how to get all the working days in 2020:
var working2020 = WorkingDaysFrom(new DateTime(2020, 1, 1))
.TakeWhile(dt => dt.Year == 2020)
.ToList();

DateTime date1 = new DateTime(2019, 12, 23);
int i = 0;
while ( i < 5)
{
date1 = date1.AddDays(1);
if (!DateSystem.IsPublicHoliday(date1, CountryCode.IT) && !DateSystem.IsWeekend(date1, CountryCode.IT))
{
i++;
}
}
but I think that you need a DateTime[] to store all the five days

This is a better and a faster way to do this without using third party libraries.
DateTime nowDate = DateTime.Now;
DateTime expectedDate;
if (nowDate.DayOfWeek == DayOfWeek.Saturday)
{
expectedDate = nowDate.AddDays(6);
}
else if (nowDate.DayOfWeek == DayOfWeek.Sunday)
{
expectedDate = nowDate.AddDays(5);
}
else
{
expectedDate = nowDate.AddDays(7);
}

I thought about the problem, and based on the LINQ suggestion Lasse-v-Karlsen made, developed this code, which gives you most flexibility:
void Main()
{
// a list of public holidays
var holidays = new List<DateTime>() {new DateTime(2020,1,1),
new DateTime(2020,12,24), new DateTime(2020,12,25), new DateTime(2020,12,26)};
// a function checking if the date is a public holiday
Func<DateTime, bool> isHoliday = (dt) => holidays.Any(a=>a==dt);
// the start date
var dt = new DateTime(2020, 07, 13);
// end date, 5 working days later
var endDate = GetWorkingDay(dt, 5, isHoliday);
// print it
Console.WriteLine(endDate?.ToString("yyyy-mm-dd"));
}
public DateTime? GetWorkingDay(DateTime dt, int skipWorkingDays = 0,
Func<DateTime, bool> holidays=null)
{
if (holidays == null) holidays = (dt) => false;
IEnumerable<DateTime> NextWorkingDay(DateTime dt)
{
while (true)
{
var day = dt.DayOfWeek;
if (day != DayOfWeek.Saturday && day != DayOfWeek.Sunday
&& !holidays.Invoke(dt)) yield return dt;
dt = dt.AddDays(1);
}
}
if (skipWorkingDays<0) return null;
if (skipWorkingDays==0) return NextWorkingDay(dt).First();
var nextXDays = NextWorkingDay(dt).Take(skipWorkingDays).ToList();
var endDate = nextXDays.OrderByDescending(d => d).First();
return endDate;
}
Whether you have a list of public holidays like in this example, or a function coming from a library telling you if a date is a public holiday or not, just feel free to modify the Lambda function isHoliday. In your case, it would be defined as:
Func<DateTime, bool> isHoliday = (dt) => DateSystem.IsPublicHoliday(dt, CountryCode.IT);

how to check if dates exist in a list of all the weeks of a year

I've got an ASP.net C# application which creates a list of all the weeks in a given year. e.g. selected year 2019, and will produce 31/12/2019 to 06/01/2019 and so on. see attached image.
To produce this I am borrowing some code from an example I found on Stack Overflow here
Now I also have another list containing dates in the format dd/MM/yyyy, this is generated from an XML file, so I wanted to only show the weeks that match dates in the weeks of the year list and populate the drop down list when a date in my XML generated list is contained within it.
For example if I had a full week or even a day in my XML generated list which fell between the 31/12/2018 to 06/01/2019 I want to show it in the drop down list.
Similarly if the XML generated list doesn't contain at least a day from that week then don't show it.
I've pasted the code I used to get the weeks of a given year below.
I'm not sure of any easy way to compare both lists. Any help would be greatly appreciated.
public List<string> FetchWeeks(int year)
{
List<string> weeks = new List<string>();
DateTime startDate = new DateTime(year, 1, 1);
startDate = startDate.AddDays(1 - (int)startDate.DayOfWeek);
DateTime endDate = startDate.AddDays(6);
while (startDate.Year < 1 + year)
{
weeks.Add(string.Format("{0:dd/MM/yyyy} to {1:dd/MM/yyyy}", startDate, endDate));
startDate = startDate.AddDays(7);
endDate = endDate.AddDays(7);
}
//DropDownList1.Items.Add(weeks);
return weeks;
}

If were trying to compare lists to determine a set of valid weeks, I would try to determine an absolute week index and use that in my work. Since weeks are not impacted by things like leap years or other date oddities, we can just count in 7-day intervals from the beginning of a known of date range. Forgive me if my C# is rusty, but something to the effect of:
public int ToWeekIndex(DateTime date)
{
// Takes any date and maps it to a value that represents the week it resides in.
Timespan ts = date - DateTime.MinValue // Monday, January 1, 0001;
return ts.Days / 7; // Integer divide, drops the remainder.
}
public DateTime FromWeekIndex(int weekIndex)
{
// Takes a week index and returns the Monday from it.
Timespan ts = new Timespan(weekIndex * 7, 0, 0, 0); // Days, hours, minutes, seconds
return DateTime.MinValue + ts;
}
Then to build out your weeks, you could do something to the effect of pseudocode:
all_weeks = []
for date in January 1, 2019 to December 31, 2019 step 7 days:
week_index = ToWeekIndex(date)
week_start = FromWeekIndex(week_index)
week_end = week_start + 7 days - 1 second
all_weeks += [week_start, week_end]

instead of a list of string for dates, use a list of object that contains the week dates and a boolean defaulted to false.
public class WeekObj
{
public string Week { get; set; }
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public bool IsValid { get; set; }
};
List<WeekObj> weeks= new WeekObj();
weeks.add(new WeekObj { "week string", startDate, endDate, false });
Loop through your list of days, and for each day go through the list of weeks and set it to true if the day is between startDate and endDate (which is now in DateTime obj), do that for false dates, no need to recompare true dates.
public static bool Between(DateTime input, DateTime date1, DateTime date2)
{
return (input >= date1 && input <= date2);
}

This is the weeks in the Year data you already have -
class WeekData
{
public DateTime WeekStartDate { get; set; }
public DateTime WeekEndDate { get; set; }
public int WeekStartDay //Gets Day in the year for the Week Start Date
{
get { return WeekStartDate.DayOfYear; }
}
public int WeekEndDay //Gets Day in the year for the Week End Date
{
get { return WeekEndDate.DayOfYear; }
}
}
Dummy WeeksInTheYear data
List<WeekData> weeks = new List<WeekData>
{
new WeekData{WeekStartDate = new DateTime(2019,10,6), WeekEndDate = new DateTime(2019,10,12)},
new WeekData{WeekStartDate = new DateTime(2019,10,13), WeekEndDate = new DateTime(2019,10,19)},
new WeekData{WeekStartDate = new DateTime(2019,10,20), WeekEndDate = new DateTime(2019,10,26)},
new WeekData{WeekStartDate = new DateTime(2019,10,27), WeekEndDate = new DateTime(2019,11,2)}
};
Dummy Dates from the XML feed
List<DateTime> xmlDates = new List<DateTime> { new DateTime(2019, 11, 1), new DateTime(2019, 10, 12), new DateTime(2019, 10, 31) };
Filtering
var weeksINeed = new List<WeekData>();
foreach (var date in xmlDates)
{
var weekINeed = weeks.Where(x => x.WeekStartDay <= date.DayOfYear && x.WeekEndDay >= date.DayOfYear)
.FirstOrDefault();
if (!weeksINeed.Any(x => x.WeekStartDay == weekINeed.WeekStartDay))
{
weeksINeed.Add(weekINeed);
}
}
Output -
foreach (var weekdata in weeksINeed.OrderBy(x=>x.WeekStartDay))
{
Console.WriteLine($"WeekStartDate - {weekdata.WeekStartDate} WeekEndDate - {weekdata.WeekEndDate}");
}

Using some extension functions and LINQ, you can just generate the list directly from the XML Date List<string>.
First, an IEnumerable<> extension to select distinct by a lambda function:
public static class IEnumerableExt {
public static IEnumerable<T> DistinctBy<T, TKey>(this IEnumerable<T> src, Func<T, TKey> keySelector, IEqualityComparer<TKey> comparer = null) {
var seenKeys = new HashSet<TKey>(comparer);
foreach (var e in src)
if (seenKeys.Add(keySelector(e)))
yield return e;
}
}
Then some calendar extensions using the built-in ISOWeek methods to get the week of year (Based on your week date ranges, I assume you are using ISO 8601 Weeks):
public static class CalendarExt {
public static int GetISO8601WeekOfYear(this DateTime aDate) => ISOWeek.GetWeekOfYear(aDate);
public static DateTime FirstDateOfYear(this DateTime d) => new DateTime(d.Year, 1, 1);
public static DateTime FirstDateOfISO8601Week(this DateTime aDate) => aDate.AddDays(-(((int)aDate.DayOfWeek + 6) % 7));
public static DateTime LastDateofISO8601Week(this DateTime aDate) => aDate.FirstDateOfISO8601Week().AddDays(6);
public static DateTime FirstDateOfISO8601Week(int year, int weekNum) => ISOWeek.ToDateTime(year, weekNum, DayOfWeek.Monday);
public static DateTime LastDateofISO8601Week(int year, int weekNum) => FirstDateOfISO8601Week(year, weekNum).AddDays(6);
// for .Net without ISOWeek
//public static DateTime FirstDateOfISO8601Week(this DateTime aDate) => aDate.AddDays(-(((int)aDate.DayOfWeek + 6) % 7));
//public static int GetISO8601WeekOfYear(this DateTime aDate) =>
// CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(aDate.AddDays(DayOfWeek.Monday <= aDate.DayOfWeek && aDate.DayOfWeek <= DayOfWeek.Wednesday ? 3 : 0), CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
}
Finally, given your list of string dates from XML in xmlDateStrings, you can compute the week ranges list:
var currentCulture = CultureInfo.CurrentCulture;
var ans = xmlDateStrings.Select(ds => DateTime.ParseExact(ds, "dd/MM/yyyy", currentCulture))
.DistinctBy(d => d.GetISO8601WeekOfYear())
.OrderBy(d => d) // assume XML is unsorted
.Select(d => $"{d.FirstDateOfISO8601Week().ToString("dd/MM/yyyy")} to {d.LastDateofISO8601Week().ToString("dd/MM/yyyy")}")
.ToList();

Get dates on certain weekday between two dates

I receive a start and end DateTime.
From this, I want to create a List<DateTime> of all the dates that are between these two dates, but only on specified weekdays, such as the Monday.

You can generate a list of dates as explained in Create an array or List of all dates between two dates:
public List<DateTime> GetDatesBetween(DateTime start, DateTime end)
{
var dates = Enumerable.Range(0, 1 + end.Subtract(start).Days)
.Select(offset => start.AddDays(offset))
.ToList();
return dates;
}
Now to filter this list to only include weekdays you're interested in is equally trivial by selecting only dates Where() the DayOfWeek property is one of the requested weekdays:
public List<DateTime> GetDatesBetween(DateTime start, DateTime end, params DayOfWeek[] weekdays)
{
bool allDays = weekdays == null || !weekdays.Any();
var dates = Enumerable.Range(0, 1 + end.Subtract(start).Days)
.Select(offset => start.AddDays(offset))
.Where(d => allDays || weekdays.Contains(d.DayOfWeek))
.ToList();
return dates;
}

Bellow function return a List<DateTime> contains all dates from startDate to endDate have given dayOfWeek:
public static List<DateTime> Get_DayofWeek_DatesBetween(DateTime startDate, DateTime endDate, DayOfWeek dayOfWeek)
{
List<DateTime> list = new List<DateTime>();
// Total dates in given range. "+ 1" include endDate
double totalDates = (endDate.Date - startDate.Date).TotalDays + 1;
// Find first "dayOfWeek" date from startDate
int i = dayOfWeek - startDate.DayOfWeek;
if (i < 0) i += 7;
// Add all "dayOfWeek" dates in given range
for (int j = i; j < totalDates; j += 7) list.Add(startDate.AddDays(j));
return list;
}

Generate Service Schedule between two Dates in .net

I am working on an Asp.net project using C#. I am facing a problem in this project. This task based on service scheduled according to condition.
Problem:
Two textboxes for dates, one dropdownlist for type
First I have selected two dates according to type generate scheduled.
For example:
I have selected dates 14/03/2014 to 14/6/2014 and type Monthly
Monthly means increase value by 1 month
So the output should look like this
14/04/2014
14/05/2014
14/06/2014
There are three dates that are scheduled between two date range
Question:
How to achieve this task ?
Sorry for poor English.....

Looping and adding one month at a time should work
public IEnumerable<DateTime> GenerateDates(DateTime start, DateTime end)
{
var dates = new List<DateTime>();
var date = new DateTime(start.Year, start.Month, start.Day);
while (date.Month <= end.Month && date.Year <= end.Year)
{
date = date.AddMonths(1);
dates.Add(date);
}
return dates;
}

var listDates = GetDates(new DateTime(2014, 3, 14), new DateTime(2014, 6, 14), "Day").ToList();
public IEnumerable<DateTime> GetDates(DateTime from, DateTime to,string type)
{
switch (type)
{
case "Month":
{
for (var dt = from.AddMonths(1); dt <= to; dt=dt.AddMonths(1))
{
yield return dt;
}
break;
}
case "Day":
{
for (var dt = from.AddDays(1); dt <= to; dt = dt.AddDays(1))
{
yield return dt;
}
break;
}
}
}
If you need to include the '14/03/2014' in the result, just remove from.AddMonths(1) from the for loop

From your question I assume that there are several modes, not just MONTHLY. Therefore I'd propose to add a registry that contains the possible modes and the function that is used to determine the next date. This registry is easily extensible if you want to offer some more modes. The sample uses a string key, but you can also use a enum.
As it is implemented now, the start date is included in the list of dates whereas the end date isn't. You can change this by tweaking the while loop.
class ScheduleDateProvider
{
private static readonly Dictionary<string, Func<DateTime, DateTime>> modesDict;
static ScheduleDateProvider()
{
// Register modes
modesDict = new Dictionary<string, Func<DateTime, DateTime>>();
modesDict.Add("Quaterly", (dt) => dt.AddMonths(3) );
modesDict.Add("Monthly", (dt) => dt.AddMonths(1) );
modesDict.Add("Weekly", (dt) => dt.AddDays(7) );
modesDict.Add("Daily", (dt) => dt.AddDays(1) );
}
public IEnumerable<DateTime> GetDatesInRange(DateTime startDate, DateTime endDate, string mode)
{
// Assemble dates in a list
var getNextDateFct = modesDict[mode];
var lst = new List<DateTime>();
while(startDate < endDate)
{
lst.Add(startDate);
startDate = getNextDateFct(startDate);
}
return lst.AsReadOnly();
}
}
The following code shows how to use the code:
void Main()
{
DateTime startDate = DateTime.Today;
DateTime endDate = DateTime.Today.AddYears(1);
string selectedMode = "Monthly";
var scheduleDateProv = new ScheduleDateProvider();
var dates = scheduleDateProv.GetDatesInRange(startDate, endDate, selectedMode);
foreach(var dt in dates)
Console.WriteLine(dt.ToShortDateString());
}

How do I loop through a date range?

I'm not even sure how to do this without using some horrible for loop/counter type solution. Here's the problem:
I'm given two dates, a start date and an end date and on a specified interval I need to take some action. For example: for every date between 3/10/2009 on every third day until 3/26/2009 I need to create an entry in a List. So my inputs would be:
DateTime StartDate = "3/10/2009";
DateTime EndDate = "3/26/2009";
int DayInterval = 3;
and my output would be a list that has the following dates:
3/13/2009
3/16/2009
3/19/2009
3/22/2009
3/25/2009
So how the heck would I do something like this? I thought about using a for loop that would iterate between every day in the range with a separate counter like so:
int count = 0;
for(int i = 0; i < n; i++)
{
count++;
if(count >= DayInterval)
{
//take action
count = 0;
}
}
But it seems like there could be a better way?

Well, you'll need to loop over them one way or the other. I prefer defining a method like this:
public IEnumerable<DateTime> EachDay(DateTime from, DateTime thru)
{
for(var day = from.Date; day.Date <= thru.Date; day = day.AddDays(1))
yield return day;
}
Then you can use it like this:
foreach (DateTime day in EachDay(StartDate, EndDate))
// print it or whatever
In this manner you could hit every other day, every third day, only weekdays, etc. For example, to return every third day starting with the "start" date, you could just call AddDays(3) in the loop instead of AddDays(1).

I have a Range class in MiscUtil which you could find useful. Combined with the various extension methods, you could do:
foreach (DateTime date in StartDate.To(EndDate).ExcludeEnd()
.Step(DayInterval.Days())
{
// Do something with the date
}
(You may or may not want to exclude the end - I just thought I'd provide it as an example.)
This is basically a ready-rolled (and more general-purpose) form of mquander's solution.

For your example you can try
DateTime StartDate = new DateTime(2009, 3, 10);
DateTime EndDate = new DateTime(2009, 3, 26);
int DayInterval = 3;
List<DateTime> dateList = new List<DateTime>();
while (StartDate.AddDays(DayInterval) <= EndDate)
{
StartDate = StartDate.AddDays(DayInterval);
dateList.Add(StartDate);
}

Code from #mquander and #Yogurt The Wise used in extensions:
public static IEnumerable<DateTime> EachDay(DateTime from, DateTime thru)
{
for (var day = from.Date; day.Date <= thru.Date; day = day.AddDays(1))
yield return day;
}
public static IEnumerable<DateTime> EachMonth(DateTime from, DateTime thru)
{
for (var month = from.Date; month.Date <= thru.Date || month.Month == thru.Month; month = month.AddMonths(1))
yield return month;
}
public static IEnumerable<DateTime> EachDayTo(this DateTime dateFrom, DateTime dateTo)
{
return EachDay(dateFrom, dateTo);
}
public static IEnumerable<DateTime> EachMonthTo(this DateTime dateFrom, DateTime dateTo)
{
return EachMonth(dateFrom, dateTo);
}

1 Year later, may it help someone,
This version includes a predicate, to be more flexible.
Usage
var today = DateTime.UtcNow;
var birthday = new DateTime(2018, 01, 01);
Daily to my birthday
var toBirthday = today.RangeTo(birthday);
Monthly to my birthday, Step 2 months
var toBirthday = today.RangeTo(birthday, x => x.AddMonths(2));
Yearly to my birthday
var toBirthday = today.RangeTo(birthday, x => x.AddYears(1));
Use RangeFrom instead
// same result
var fromToday = birthday.RangeFrom(today);
var toBirthday = today.RangeTo(birthday);
Implementation
public static class DateTimeExtensions
{
public static IEnumerable<DateTime> RangeTo(this DateTime from, DateTime to, Func<DateTime, DateTime> step = null)
{
if (step == null)
{
step = x => x.AddDays(1);
}
while (from < to)
{
yield return from;
from = step(from);
}
}
public static IEnumerable<DateTime> RangeFrom(this DateTime to, DateTime from, Func<DateTime, DateTime> step = null)
{
return from.RangeTo(to, step);
}
}
Extras
You could throw an Exception if the fromDate > toDate, but I prefer to return an empty range instead []

DateTime startDate = new DateTime(2009, 3, 10);
DateTime stopDate = new DateTime(2009, 3, 26);
int interval = 3;
for (DateTime dateTime=startDate;
dateTime < stopDate;
dateTime += TimeSpan.FromDays(interval))
{
}

DateTime begindate = Convert.ToDateTime("01/Jan/2018");
DateTime enddate = Convert.ToDateTime("12 Feb 2018");
while (begindate < enddate)
{
begindate= begindate.AddDays(1);
Console.WriteLine(begindate + " " + enddate);
}

According to the problem you can try this...
// looping between date range
while (startDate <= endDate)
{
//here will be your code block...
startDate = startDate.AddDays(1);
}
thanks......

DateTime startDate = new DateTime(2009, 3, 10);
DateTime stopDate = new DateTime(2009, 3, 26);
int interval = 3;
while ((startDate = startDate.AddDays(interval)) <= stopDate)
{
// do your thing
}

Here are my 2 cents in 2020.
Enumerable.Range(0, (endDate - startDate).Days + 1)
.ToList()
.Select(a => startDate.AddDays(a));

You can use the DateTime.AddDays() function to add your DayInterval to the StartDate and check to make sure it is less than the EndDate.

You might consider writing an iterator instead, which allows you to use normal 'for' loop syntax like '++'. I searched and found a similar question answered here on StackOverflow which gives pointers on making DateTime iterable.

you have to be careful here not to miss the dates when in the loop a better solution would be.
this gives you the first date of startdate and use it in the loop before incrementing it and it will process all the dates including the last date of enddate hence <= enddate.
so the above answer is the correct one.
while (startdate <= enddate)
{
// do something with the startdate
startdate = startdate.adddays(interval);
}

you can use this.
DateTime dt0 = new DateTime(2009, 3, 10);
DateTime dt1 = new DateTime(2009, 3, 26);
for (; dt0.Date <= dt1.Date; dt0=dt0.AddDays(3))
{
//Console.WriteLine(dt0.Date.ToString("yyyy-MM-dd"));
//take action
}

Iterate every 15 minutes
DateTime startDate = DateTime.Parse("2018-06-24 06:00");
DateTime endDate = DateTime.Parse("2018-06-24 11:45");
while (startDate.AddMinutes(15) <= endDate)
{
Console.WriteLine(startDate.ToString("yyyy-MM-dd HH:mm"));
startDate = startDate.AddMinutes(15);
}

#jacob-sobus and #mquander and #Yogurt not exactly correct.. If I need the next day I wait 00:00 time mostly
public static IEnumerable<DateTime> EachDay(DateTime from, DateTime thru)
{
for (var day = from.Date; day.Date <= thru.Date; day = day.NextDay())
yield return day;
}
public static IEnumerable<DateTime> EachMonth(DateTime from, DateTime thru)
{
for (var month = from.Date; month.Date <= thru.Date || month.Year == thru.Year && month.Month == thru.Month; month = month.NextMonth())
yield return month;
}
public static IEnumerable<DateTime> EachYear(DateTime from, DateTime thru)
{
for (var year = from.Date; year.Date <= thru.Date || year.Year == thru.Year; year = year.NextYear())
yield return year;
}
public static DateTime NextDay(this DateTime date)
{
return date.AddTicks(TimeSpan.TicksPerDay - date.TimeOfDay.Ticks);
}
public static DateTime NextMonth(this DateTime date)
{
return date.AddTicks(TimeSpan.TicksPerDay * DateTime.DaysInMonth(date.Year, date.Month) - (date.TimeOfDay.Ticks + TimeSpan.TicksPerDay * (date.Day - 1)));
}
public static DateTime NextYear(this DateTime date)
{
var yearTicks = (new DateTime(date.Year + 1, 1, 1) - new DateTime(date.Year, 1, 1)).Ticks;
var ticks = (date - new DateTime(date.Year, 1, 1)).Ticks;
return date.AddTicks(yearTicks - ticks);
}
public static IEnumerable<DateTime> EachDayTo(this DateTime dateFrom, DateTime dateTo)
{
return EachDay(dateFrom, dateTo);
}
public static IEnumerable<DateTime> EachMonthTo(this DateTime dateFrom, DateTime dateTo)
{
return EachMonth(dateFrom, dateTo);
}
public static IEnumerable<DateTime> EachYearTo(this DateTime dateFrom, DateTime dateTo)
{
return EachYear(dateFrom, dateTo);
}

If you convert your dates to OADate you can loop thru them as you would do with any double number.
DateTime startDate = new DateTime(2022, 1, 1);
DateTime endDate = new DateTime(2022, 12, 31);
for (double loopDate = startDate.ToOADate(); loopDate <= endDate.ToOADate(); loopDate++)
{
DateTime selectedDate;
selectedDate = DateTime.FromOADate(loopDate);
}