Simplest way to calculate anniversary given a date in the past? - c#

i need a function that calculates if there is an upcoming anniversary for a person given a start date in the past and today's current date. I found this code below but looking at the below code and I have the feeling that there is a much simpler way to calculate this without required this for loop:
private const int ANNIVERSARY_ALERT = 10;
public virtual string UpcomingMilestone
{
get
{
var years = Years() + 2;
for (int year = 0; year < years; year++)
{
int days = year * 365;
int dayDiff = days - NumberOfDays;
if (dayDiff == 0)
{
return year + " year milestone";
}
if (dayDiff < ANNIVERSARY_ALERT && dayDiff > 0)
{
return year + " year milestone in " + dayDiff + " days";
}
}
return string.Empty;
}
}
public virtual int NumberOfDays
{
get
{
TimeSpan ts = DateTime.Today - StartDate.Value;
return (int)ts.TotalDays;
}
}
public virtual int Years()
{
TimeSpan span = DateTime.Now.Subtract(StartDate.Value);
return (int)(span.Days / 365.25); // leap years included
}
Can anyone suggest a way to calculate this above without having to do this loop? This is more for code maintainability versus any performance considerations.

Use the relevant parts of the startdate to compose a new DateTime:
//My birthday, feel free to put this date in your calendars!
var startDate = new DateTime(1976, 2, 29);
//Get the anniversary date for this year
DateTime nextAnniversary;
try
{
nextAnniversary = new DateTime(DateTime.Today.Year, startDate.Month, startDate.Day);
}
catch(ArgumentOutOfRangeException)
{
//DateTime conversion failed, try next day in the year
nextAnniversary = new DateTime(DateTime.Today.Year, startDate.AddDays(1).Month, startDate.AddDays(1).Day);
}
//Check if this year's anniversary has already happened
if(nextAnniversary < DateTime.Today) nextAnniversary = nextAnniversary.AddYears(1);

This should do it. You need to provide TimeSpan range that can be a day or a week, and date which you are matching anniversary to.
public bool Upcomming(DateTime date, TimeSpan range){
var newdate = new Date(DateTime.Now.Year, date.Month, date.Day);
return newdate - DateTime.Now < range;
}

int anniversaryYear = DateTime.Now.Year - StartDate.Year + 1;
DateTime nextAnniversary = StartDate.AddYears(anniversaryYear);
if (nextAnniversary == DateTime.Now)
{
return anniverasryYear + " year milestone";
}
if (DateTime.Now > nextAnniverasry)
{
anniverasryYear++;
nextAnniversary = StartDate.AddYears(anniversaryYear);
}
var daysTillNext = Math.Abs( (nextAnniversary - DateTime.Now).TotalDays );
return string.Format("{0} milestone in {1}", anniversaryYear, daysTillNext);

These methods should be sufficient for your purposes.
public DateTime GetNextAnniversaryDate(DateTime anniversary)
{
var today = DateTime.Today;
var year = anniversary.Month < today.Month ||
(anniversary.Month == today.Month && anniversary.Day < today.Day)
? today.Year + 1 : today.Year;
return anniversary.Month == 2 && anniversary.Day == 29 &&
!DateTime.IsLeapYear(year)
? new DateTime(year, 2, 28)
: new DateTime(year, anniversary.Month, anniversary.Day);
}
public int GetDaysUntilNextAnniversary(DateTime anniversary)
{
var nextDate = GetNextAnniversaryDate(anniversary);
return (int)(nextDate - DateTime.Today).TotalDays;
}
Note that we are specifically electing to celebrate leap-day anniversaries on Feb 28th when the anniversary year is not a leap year. You could change that to March 1 if desired.
Also note that this question assumes that the day of the person in question is the same day as the computer's local clock. This might not be true, for example if the local machine is in a time zone that is ahead of the user's time zone, then it might be one day off. If you want to take that into consideration, then you could use TimeZoneInfo and DateTime.UtcNow. Or you could use Noda Time. More about this on my blog.

Related

Calculating no of weekends in between the two given date and time fields by considering the time difference and output the difference in minutes

I have two fields startdate and enddate. I need to calculate how many weekends in between two date and time fields and show the result in minutes.
For example start date is 01/11/2019 00:00:00 and end date as 03/11/2019 11:00:00. Below code is returning the difference in minutes correctly as 2100 minutes but when I keep the dates as02/11/2019 08:00 and 03/11/2019 00:00 I am getting the result as 1440 but my expected result is 960 minutes.
I understand that's because I am adding 1440 in code so how to correct this?
public double CountOfWeekEnds(DateTime startDate, DateTime endDate)
{
double weekEndCount = 0;
if (startDate > endDate)
{
DateTime temp = startDate;
startDate = endDate;
endDate = temp;
}
TimeSpan diff = endDate - startDate;
int days = diff.Days;
for (var i = 0; i <= days; i++)
{
var testDate = startDate.AddDays(i);
if (testDate.DayOfWeek == DayOfWeek.Saturday || testDate.DayOfWeek == DayOfWeek.Sunday)
{
if (testDate.Date < endDate.Date)
{
weekEndCount += 1440; // 24h * 60 min
}
else
{
var todayStart = new DateTime(testDate.Year, testDate.Month, testDate.Day, 0, 0, 0);
var difference = (endDate - todayStart).TotalMinutes;
weekEndCount += difference;
}
}
}
return weekEndCount;
}
OK, i simplified what i said a little down to:
DateTime start = new DateTime(2019,11,1,0,0,0);
DateTime end = new DateTime(2019, 11, 3, 11, 0, 0);
TimeSpan diff = end - start;
Console.WriteLine(diff.TotalDays);
int total = 0;
for (int i = 0; i<Math.Ceiling(diff.TotalDays); i++)
{
DateTime test = start.AddDays(i);
Console.WriteLine(test.DayOfWeek);
if (test.DayOfWeek == DayOfWeek.Saturday || test.DayOfWeek == DayOfWeek.Sunday)
{
if (test.Date==start.Date)
{
Console.WriteLine("start");
total += (23 - start.Hour) * 60 + (60 - start.Minute);
}
else if (test.Date==end.Date)
{
Console.WriteLine("end");
total += end.Hour * 60 + end.Minute;
}
else
{
total += 24 * 60;
}
}
Console.WriteLine(test + " total " + total);
}
Console.WriteLine("done");
Console.WriteLine(total);
which counts all saturdays and sundays and allows for start and ends to be partials
(and can someone send a keyboard with actual keys this membrain lark is hampering typings)
Trying to remain as much of the original code as possible, only three minor changes have to be made:
1. Use the actual dates to calculate diff:
TimeSpan diff = endDate.Date - startDate.Date; instead of TimeSpan diff = endDate - startDate;
This is because later in the upcoming for-loop you are trying to evaluate each date in order to say if is a saturday or sunday. Otherwise, you are evaluating if the date 24 (, 48, …) hours after your starting time stamp is a saturday or sunday.
2. Use testDate instead of todayStart in order to calculate difference
difference = (endDate - testDate).TotalMinutes;
instead of
var todayStart = new DateTime(testDate.Year, testDate.Month, testDate.Day, 0, 0, 0);
var difference = (endDate - todayStart).TotalMinutes;
This is because testDate does contain the hours and minutes to calculate the difference in minutes. Otherwise you are just ignoring the day time of the starting day. Note that this correction can lead to a negative difference value if the startDate day time is later than the endDate day time.
3. do not add a whole day if there is only one day to examine in total
That means that if startDate.Date == endDate.Date, you should just calculate the difference between the dates.
if (testDate.Date < endDate.Date && startDate.Date != endDate.Date)
This has to be done because of the code logic: a full day is added for every new day other than the final day and for the final day ~24hours are added or substracted to the final value depending on the day times of the startDate and endDate.
The complete corrected code:
public static double CountOfWeekEnds(DateTime startDate, DateTime endDate)
{
double weekEndCount = 0;
if (startDate > endDate)
{
DateTime temp = startDate;
startDate = endDate;
endDate = temp;
}
TimeSpan diff = endDate.Date - startDate.Date; //instead of endDate - startDate
int days = diff.Days;
for (var i = 0; i <= days; i++)
{
var testDate = startDate.AddDays(i);
//Console.WriteLine(testDate);
if (testDate.DayOfWeek == DayOfWeek.Saturday || testDate.DayOfWeek == DayOfWeek.Sunday) //only weekends count
{
if (testDate.Date < endDate.Date && startDate.Date != endDate.Date) { // added startDate.Date != endDate.Date
weekEndCount += 1440; // 24h * 60 min
//Console.WriteLine("************************add 1440 ");
}
else
{
double difference;
difference = (endDate - testDate).TotalMinutes; //instead of endDate - todayStart
//Console.WriteLine("************************add " + difference);
weekEndCount += difference;
}
}
}
//return days;
return weekEndCount;
}
You need to have a look at this condition:
if (testDate.Date < endDate.Date)
It means that "as long as the ticks of testDate is less than the ticks of endDate".
This condition will be true for all conditions that makes your variable "days" positive.
I think you need to extend this, condition e.g.
if ((endDate - todayStart).TotalMinutes > 1440 )
This way it will check whether it is AT LEAST 24 hours earlier. If it isn't it should go forth with your "else" condition and take the used fraction of the start day into consideration.
Here is a (somewhat) simple solution. Please note that the code could (and probably should) be refactored if it was to be production code. But I tried to optimize it for understandability, since it was your first post...
public static int CalculateWeekendMinutes(DateTime start, DateTime end)
{
int weekendMinutes = 0;
// First and last day will be handled seperately in the end
var firstFullDay = start.AddDays(1).Date;
var lastFullDay = end.AddDays(-1).Date;
TimeSpan limitedSpan = lastFullDay - firstFullDay;
int spanLengthDays = (int)limitedSpan.TotalDays;
var dateIterator = firstFullDay;
// Looping over the limited span allows us to analyse all the full days
while (dateIterator <= lastFullDay)
{
if (dateIterator.DayOfWeek == DayOfWeek.Saturday || dateIterator.DayOfWeek == DayOfWeek.Sunday)
{
weekendMinutes += (24 * 60);
}
dateIterator = dateIterator.AddDays(1);
}
// Finally we can calculate the partial days and add that to our total
weekendMinutes += CalculateMinutesOnFirstDay(start);
weekendMinutes += CalculateMinutesOnLastDay(end);
return weekendMinutes;
}
// Helps us calculate the minutes of the first day in the span
private static int CalculateMinutesOnFirstDay(DateTime date)
{
if (date.DayOfWeek == DayOfWeek.Saturday || date.DayOfWeek == DayOfWeek.Sunday)
{
// We want to know how many minutes there are UNTIL the next midnight
int minutes = (int)(date.Date.AddDays(1) - date).TotalMinutes;
return minutes;
}
else
{
return 0;
}
}
// Helps us calculate the minutes of the last day in the span
private static int CalculateMinutesOnLastDay(DateTime date)
{
if (date.DayOfWeek == DayOfWeek.Saturday || date.DayOfWeek == DayOfWeek.Sunday)
{
// We want to know how many minutes there are SINCE the last midnight
int minutes = (int)(date - date.Date).TotalMinutes;
return minutes;
}
else
{
return 0;
}
}

Date Time and Formula Improvement C#

I got here a scenario where I input an information but the code does does not work. What happen is when I input 12/11/2015, the Address2Panel shows. Which is wrong because there no more date that I can input because Person A is born in 12/11/2015. The logic should Enter addresses for the past 5 years. But it goes wrong if the Birthdate gap is not lesser the 5 years from the current date.
Person A Birthday = 12/11/2015
Person A StartLiving = 12/11/2015 because its the day he/she was born.
Should not display Address2Panel
int CurrentDateInMonths = (((DateTime.Today.Year) * 12) + (DateTime.Today.Month));
static int AlienMonthsAtCurrentAddress = 0;
DateTime myDateTime;
//LivedHere = 12/11/2015
myDateTime = DateTime.Parse(LivedHere.Text);
AlienMonthsAtCurrentAddress = (CurrentDateInMonths - (((Convert.ToInt16(myDateTime.Year)) * 12) + Convert.ToInt16(myDateTime.Month)));
if (AlienMonthsAtCurrentAddress < 60)
{
Address2Panel.Visible = true;//shows the Address2Panel
}
else
{
ClearAddress2Panel();//hides also the Address2Panel
}
Any suggestion how should I improve my formula and date time manipulation?
no need to convert date into months, subtract dates using DateTime.Subtract method :
From MSDN, DateTime.Subtract Method subtracts the specified date and time from this instance.It returns a TimeSpan object which has a property Days
static int AlienMonthsAtCurrentAddress = 0;
try
{
DateTime myDateTime;
myDateTime = DateTime.Parse(LivedHere.Text);
// If you don't wish to subtract from today's date use required date in place of DateTime.Now
TimeSpan span = DateTime.Now.Subtract ( myDateTime );
if (span.Days < 60)
{
Address2Panel.Visible = true;//shows the Address2Panel
}
else
{
ClearAddress2Panel();//hides also the Address2Panel
}
}
catch { }
You could check years, months and days with a separately logic, and then get them all together:
DateTime date = new DateTime(2015,11,12)
DateTime input = getDate()
int years = input.Year - date.Year - 1
years += If(input.Month > date.Month, 1, 0)
years += If(input.Month = date.Month AndAlso input.Day >= date.Day, 1, 0)
This will output the exact number of years between two days (truncating the resulting integer). You'll just have to compare it to 5, in your case

Calculating days left until the next specified day

In a scenario where you would need to calculate the next 'Billing date' if the DAY (2nd, 25th, etc) is known, how can you calculate the number of days left until the next bill payment?
Explanation:
Tom's bill gets generated on the 4th of every month
What's the best way/logic to calculate the days left until the next bill? For example, if today is the 28th of this month, the result would be 6 days left
What we know:
Bill Generation Date is known
Today's Date is known
What I've done so far:
int billingDay = 4; //The day the bill gets generated every month
DateTime today = DateTime.Today; //Today's date
How would I continue this to calculate the next billing date?
P.S: Sorry if this sounds lame, I just couldn't wrap my head around it :)
I think this works:
private int GetNumDaysToNextBillingDate(int billingDayOfMonth)
{
DateTime today = DateTime.Today;
if (today.Day <= billingDayOfMonth)
{
return (new DateTime(today.Year, today.Month, billingDayOfMonth) - today).Days;
}
else
{
var oneMonthFromToday = today.AddMonths(1);
var billingDateNextMonth =
new DateTime(oneMonthFromToday.Year,
oneMonthFromToday.Month, billingDayOfMonth);
return (billingDateNextMonth - today).Days;
}
}
How about:
int billingDay = 4;
DateTime today = DateTime.UtcNow;
DateTime billing = today.Day >= billingDay
? new DateTime(today.AddMonths(1).Year, today.AddMonths(1).Month, billingDay)
: new DateTime(today.Year, today.Month, billingDay);
TimeSpan left = billing - today;
This uses a loop but is less prone to error as it takes into account month and year changes:
int DaysUntilBilling(int billingDay, DateTime referenceDate)
{
int count = 0;
while (referenceDate.AddDays(count).Day != billingDay)
{
count++;
};
return count;
}
You of course don't need to pass a DateTime in as an argument if you are always using today's date, but this helps to test that that for different inputs, you get the desired output:
int billingDay = 4;
DaysUntilBilling(billingDay, DateTime.Now); //26 (today is 9th Aug 2016)
DaysUntilBilling(billingDay, new DateTime(2016, 09, 03); //1
DaysUntilBilling(billingDay, new DateTime(2016, 09, 04); //0
DaysUntilBilling(billingDay, new DateTime(2016, 08, 05); //30
DaysUntilBilling(billingDay, new DateTime(2016, 12, 19); //16
This link might help you :
https://msdn.microsoft.com/en-us/library/system.datetime.daysinmonth(v=vs.110).aspx
What you can do is something like this:
int daysUntilBill = 0;
int billingDay = 4;
DateTime today = DateTime.Today;
if (billingDay > today.Day) {
daysUntilBill = billingDay - today.Day;
} else {
int daysLeftInMonth = DateTime.DaysInMonth(today.Year, today.Month) - today.Day;
daysUntilBill = billingDay + daysLeftInMonth;
}
or slightly more concise
int daysUntilBill = (billingDay >= today.Day)
? billingDay - today.Day
: billingDay + DateTime.DaysInMonth(today.Year, today.Month) - today.Day;
This properly handles the year ending too, since it doesn't try to wrap around.
First you need to determine if the current date is on or before the billing day and if it is just subtract the current day of the month. Otherwise you have to determine the next billing date in the following month.
public int DaysToNextBill(int billingDay)
{
var today = DateTime.Today;
if(today.Day <= billingDay)
return billingDay - today.Day;
var nextMonth = today.AddMonth(1);
var nextBillingDate = new DateTime(nextMonth.Year, nextMonth.Month, billingDay)
return (nextBillingDate - today).Days;
}
The only thing left to deal with is if billingDay is greater than the number of days in the current or following month.

Date algorithm - Add days without considering leap years

The system I'm working on is built and configured in such a way, where users cannot choose leap years when setting up a recurring payment. This results in all the date-math behind the scenes having to ignore leap years. (I didn't choose this, but this is how it was written)
I have to write a method that takes in a DateTime value, and adds days to the date, ignoring leap years, which essentially means ignoring Feb 29th and pretending it doesn't exist.
For example, If I'm adding 365 days to 1/1/2016, that should result in 1/1/2017, not 12/31/2016.
I'm using .NET, so I can make use of DateTime.IsLeapYear, and other helper methods.
This is a work in progress, and here is what I have so far. I started taking a simpler route, and I'm now realizing that it's going to require a more complex algorithm.
public static DateTime AddDaysToDateWithLeapYearConsideration(DateTime date, int daysToAdd)
{
// Nothing to do
if (daysToAdd == 0)
{
return date;
}
// NOTE: This is an invalid approach; using DateTime.AddDays will take leap years into account
DateTime dateWithAddedDays = date.AddDays(daysToAdd);
const int FEB_28_DAY_OF_YEAR = 59;
int daysToSubtractForLeapYearConsideration = 0;
// The year is a leap year, which is under the feb 28 day threshold, and we're adding enough days to push it over the feb 28 day threshold
// This will result in .NET taking into account the feb 29th (the leap year day), but we have to subtract that leap year day since the system doesn't take feb 29th into account
if (DateTime.IsLeapYear(date.Year) && date.DayOfYear < FEB_28_DAY_OF_YEAR && (date.DayOfYear + daysToAdd > FEB_28_DAY_OF_YEAR))
{
daysToSubtractForLeapYearConsideration++;
}
// The resulting date (after the days are added or subtracted) is a leap year, whose day is past the feburary 28 day threshold, and it's not the same year as the date (i.e. it spans across "n" years)
if (DateTime.IsLeapYear(dateWithAddedDays.Year) && dateWithAddedDays.DayOfYear > FEB_28_DAY_OF_YEAR && dateWithAddedDays.Year != date.Year)
{
daysToSubtractForLeapYearConsideration++;
}
// We determined if the original date should be leap year considered, as well as the resulting date/year with the days added. Now see if there are any years in between
// that we should consider
bool isThereAYearRangeThatWeNeedToEvaluateLeapYearsFor = Math.Abs(date.Year - dateWithAddedDays.Year) > 0;
if (isThereAYearRangeThatWeNeedToEvaluateLeapYearsFor)
{
for (int leapYearEvalIndex = Math.Min(date.Year, dateWithAddedDays.Year); leapYearEvalIndex <= Math.Max(date.Year, dateWithAddedDays.Year); leapYearEvalIndex++)
{
bool isYearPartOfTheYearsThatWeveAlreadyChecked = leapYearEvalIndex == date.Year || leapYearEvalIndex == dateWithAddedDays.Year;
if (!isYearPartOfTheYearsThatWeveAlreadyChecked && DateTime.IsLeapYear(leapYearEvalIndex))
{
daysToSubtractForLeapYearConsideration++;
}
}
}
DateTime dateResult = date.AddDays(daysToAdd - daysToSubtractForLeapYearConsideration);
// The system does not allow 2/29 days, hence all this crazy date math
if (dateResult.Month == 2 && dateResult.Day == 29)
{
dateResult = dateResult.AddDays(1);
}
return dateResult;
}
The logic has to take into account negative numbers as well (i.e. subtracting), which the above code fails on.
The above code by no means works, but I wanted to demonstrate that I'm trying to tackle the problem, and not simply asking without having tried anything.
Edit
I've come up with an algorithm pretty close to David's approach. (I wrote it, and then came back to StackOverflow to check responses).
public static DateTime AddDaysToDateWithLeapYearConsideration(DateTime date, int daysToAdd)
{
// Nothing to do
if (daysToAdd == 0)
{
return date;
}
DateTime dateResult = date;
// Are we adding or subtracting
bool areWeAddingDays = daysToAdd > 0;
int daysToAccountForInRegardToLeapYearDates = 0,
absDaysToAdd = Math.Abs(daysToAdd);
for (int i = 1; i <= absDaysToAdd; i++)
{
dateResult = dateResult.AddDays(areWeAddingDays ? 1 : -1);
if (dateResult.Month == 2 && dateResult.Day == 29)
{
daysToAccountForInRegardToLeapYearDates++;
}
}
dateResult = dateResult.AddDays(areWeAddingDays ? daysToAccountForInRegardToLeapYearDates : -daysToAccountForInRegardToLeapYearDates);
return dateResult;
}
Here is an extension method that works. Will also work if you're adding or subtracting enough days to span multiple leap years.
public static DateTime AddDaysWithoutLeapYear(this DateTime input, int days)
{
var output = input;
if (days != 0)
{
var increment = days > 0 ? 1 : -1; //this will be used to increment or decrement the date.
var daysAbs = Math.Abs(days); //get the absolute value of days to add
var daysAdded = 0; // save the number of days added here
while (daysAdded < daysAbs)
{
output = output.AddDays(increment);
if (!(output.Month == 2 && output.Day == 29)) //don't increment the days added if it is a leap year day
{
daysAdded++;
}
}
}
return output;
}
Might need some more testing, but without using the DateTime Add... functions or too much looping, a possible custom implementation:
public static DateTime AddDaysToDateWithLeapYearConsideration(DateTime date, int daysToAdd)
{
int year = date.Year + daysToAdd / 365, month = date.Month - 1, dir = Math.Sign(daysToAdd);
daysToAdd = (daysToAdd % 365) + date.Day;
int[] months = {31,28,31,30,31,30,31,31,30,31,30,31};
while(daysToAdd > months[month] || daysToAdd < 0){
if(dir ==1) daysToAdd -= months[month];
month += dir;
if(month == 12 || month == -1){
year += dir;
month = dir == -1 ? 11 : 0;
}
if(dir ==-1) daysToAdd += months[month]; //for reverse direction, add previous month
}
return new DateTime(year, ++month,daysToAdd);
}

Get exact days and months between two dates c# [duplicate]

How to calculate the difference in months between two dates in C#?
Is there is equivalent of VB's DateDiff() method in C#. I need to find difference in months between two dates that are years apart. The documentation says that I can use TimeSpan like:
TimeSpan ts = date1 - date2;
but this gives me data in Days. I don't want to divide this number by 30 because not every month is 30 days and since the two operand values are quite apart from each other, I am afraid dividing by 30 might give me a wrong value.
Any suggestions?
Assuming the day of the month is irrelevant (i.e. the diff between 2011.1.1 and 2010.12.31 is 1), with date1 > date2 giving a positive value and date2 > date1 a negative value
((date1.Year - date2.Year) * 12) + date1.Month - date2.Month
Or, assuming you want an approximate number of 'average months' between the two dates, the following should work for all but very huge date differences.
date1.Subtract(date2).Days / (365.25 / 12)
Note, if you were to use the latter solution then your unit tests should state the widest date range which your application is designed to work with and validate the results of the calculation accordingly.
Update (with thanks to Gary)
If using the 'average months' method, a slightly more accurate number to use for the 'average number of days per year' is 365.2425.
Here is a comprehensive solution to return a DateTimeSpan, similar to a TimeSpan, except that it includes all the date components in addition to the time components.
Usage:
void Main()
{
DateTime compareTo = DateTime.Parse("8/13/2010 8:33:21 AM");
DateTime now = DateTime.Parse("2/9/2012 10:10:11 AM");
var dateSpan = DateTimeSpan.CompareDates(compareTo, now);
Console.WriteLine("Years: " + dateSpan.Years);
Console.WriteLine("Months: " + dateSpan.Months);
Console.WriteLine("Days: " + dateSpan.Days);
Console.WriteLine("Hours: " + dateSpan.Hours);
Console.WriteLine("Minutes: " + dateSpan.Minutes);
Console.WriteLine("Seconds: " + dateSpan.Seconds);
Console.WriteLine("Milliseconds: " + dateSpan.Milliseconds);
}
Outputs:
Years: 1
Months: 5
Days: 27
Hours: 1
Minutes: 36
Seconds: 50
Milliseconds: 0
For convenience, I've lumped the logic into the DateTimeSpan struct, but you may move the method CompareDates wherever you see fit. Also note, it doesn't matter which date comes before the other.
public struct DateTimeSpan
{
public int Years { get; }
public int Months { get; }
public int Days { get; }
public int Hours { get; }
public int Minutes { get; }
public int Seconds { get; }
public int Milliseconds { get; }
public DateTimeSpan(int years, int months, int days, int hours, int minutes, int seconds, int milliseconds)
{
Years = years;
Months = months;
Days = days;
Hours = hours;
Minutes = minutes;
Seconds = seconds;
Milliseconds = milliseconds;
}
enum Phase { Years, Months, Days, Done }
public static DateTimeSpan CompareDates(DateTime date1, DateTime date2)
{
if (date2 < date1)
{
var sub = date1;
date1 = date2;
date2 = sub;
}
DateTime current = date1;
int years = 0;
int months = 0;
int days = 0;
Phase phase = Phase.Years;
DateTimeSpan span = new DateTimeSpan();
int 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;
}
}
You could do
if ( date1.AddMonths(x) > date2 )
If you want the exact number of full months, always positive (2000-01-15, 2000-02-14 returns 0), considering a full month is when you reach the same day the next month (something like the age calculation)
public static int GetMonthsBetween(DateTime from, DateTime to)
{
if (from > to) return GetMonthsBetween(to, from);
var monthDiff = Math.Abs((to.Year * 12 + (to.Month - 1)) - (from.Year * 12 + (from.Month - 1)));
if (from.AddMonths(monthDiff) > to || to.Day < from.Day)
{
return monthDiff - 1;
}
else
{
return monthDiff;
}
}
Edit reason: the old code was not correct in some cases like :
new { From = new DateTime(1900, 8, 31), To = new DateTime(1901, 8, 30), Result = 11 },
Test cases I used to test the function:
var tests = new[]
{
new { From = new DateTime(1900, 1, 1), To = new DateTime(1900, 1, 1), Result = 0 },
new { From = new DateTime(1900, 1, 1), To = new DateTime(1900, 1, 2), Result = 0 },
new { From = new DateTime(1900, 1, 2), To = new DateTime(1900, 1, 1), Result = 0 },
new { From = new DateTime(1900, 1, 1), To = new DateTime(1900, 2, 1), Result = 1 },
new { From = new DateTime(1900, 2, 1), To = new DateTime(1900, 1, 1), Result = 1 },
new { From = new DateTime(1900, 1, 31), To = new DateTime(1900, 2, 1), Result = 0 },
new { From = new DateTime(1900, 8, 31), To = new DateTime(1900, 9, 30), Result = 0 },
new { From = new DateTime(1900, 8, 31), To = new DateTime(1900, 10, 1), Result = 1 },
new { From = new DateTime(1900, 1, 1), To = new DateTime(1901, 1, 1), Result = 12 },
new { From = new DateTime(1900, 1, 1), To = new DateTime(1911, 1, 1), Result = 132 },
new { From = new DateTime(1900, 8, 31), To = new DateTime(1901, 8, 30), Result = 11 },
};
I checked the usage of this method in VB.NET via MSDN and it seems that it has a lot of usages. There is no such a built-in method in C#. (Even it's not a good idea) you can call VB's in C#.
Add Microsoft.VisualBasic.dll to
your project as a reference
use
Microsoft.VisualBasic.DateAndTime.DateDiff
in your code
Use Noda Time:
LocalDate start = new LocalDate(2013, 1, 5);
LocalDate end = new LocalDate(2014, 6, 1);
Period period = Period.Between(start, end, PeriodUnits.Months);
Console.WriteLine(period.Months); // 16
(example source)
To get difference in months (both start and end inclusive), irrespective of dates:
DateTime start = new DateTime(2013, 1, 1);
DateTime end = new DateTime(2014, 2, 1);
var diffMonths = (end.Month + end.Year * 12) - (start.Month + start.Year * 12);
I just needed something simple to cater for e.g. employment dates where only the month/year is entered, so wanted distinct years and months worked in. This is what I use, here for usefullness only
public static YearsMonths YearMonthDiff(DateTime startDate, DateTime endDate) {
int monthDiff = ((endDate.Year * 12) + endDate.Month) - ((startDate.Year * 12) + startDate.Month) + 1;
int years = (int)Math.Floor((decimal) (monthDiff / 12));
int months = monthDiff % 12;
return new YearsMonths {
TotalMonths = monthDiff,
Years = years,
Months = months
};
}
.NET Fiddle
You can use Noda Time https://nodatime.org/
LocalDate start = new LocalDate(2010, 1, 5);
LocalDate end = new LocalDate(2012, 6, 1);
Period period = Period.Between(start, end, PeriodUnits.Months);
Console.WriteLine(period.Months);
You can use the DateDiff class of the Time Period Library for .NET:
// ----------------------------------------------------------------------
public void DateDiffSample()
{
DateTime date1 = new DateTime( 2009, 11, 8, 7, 13, 59 );
DateTime date2 = new DateTime( 2011, 3, 20, 19, 55, 28 );
DateDiff dateDiff = new DateDiff( date1, date2 );
// differences
Console.WriteLine( "DateDiff.Months: {0}", dateDiff.Months );
// > DateDiff.Months: 16
// elapsed
Console.WriteLine( "DateDiff.ElapsedMonths: {0}", dateDiff.ElapsedMonths );
// > DateDiff.ElapsedMonths: 4
// description
Console.WriteLine( "DateDiff.GetDescription(6): {0}", dateDiff.GetDescription( 6 ) );
// > DateDiff.GetDescription(6): 1 Year 4 Months 12 Days 12 Hours 41 Mins 29 Secs
} // DateDiffSample
Here is my contribution to get difference in Months that I've found to be accurate:
namespace System
{
public static class DateTimeExtensions
{
public static Int32 DiffMonths( this DateTime start, DateTime end )
{
Int32 months = 0;
DateTime tmp = start;
while ( tmp < end )
{
months++;
tmp = tmp.AddMonths( 1 );
}
return months;
}
}
}
Usage:
Int32 months = DateTime.Now.DiffMonths( DateTime.Now.AddYears( 5 ) );
You can create another method called DiffYears and apply exactly the same logic as above and AddYears instead of AddMonths in the while loop.
This worked for what I needed it for. The day of month didn't matter in my case because it always happens to be the last day of the month.
public static int MonthDiff(DateTime d1, DateTime d2){
int retVal = 0;
if (d1.Month<d2.Month)
{
retVal = (d1.Month + 12) - d2.Month;
retVal += ((d1.Year - 1) - d2.Year)*12;
}
else
{
retVal = d1.Month - d2.Month;
retVal += (d1.Year - d2.Year)*12;
}
//// Calculate the number of years represented and multiply by 12
//// Substract the month number from the total
//// Substract the difference of the second month and 12 from the total
//retVal = (d1.Year - d2.Year) * 12;
//retVal = retVal - d1.Month;
//retVal = retVal - (12 - d2.Month);
return retVal;
}
There's 3 cases: same year, previous year and other years.
If the day of the month does not matter...
public int GetTotalNumberOfMonths(DateTime start, DateTime end)
{
// work with dates in the right order
if (start > end)
{
var swapper = start;
start = end;
end = swapper;
}
switch (end.Year - start.Year)
{
case 0: // Same year
return end.Month - start.Month;
case 1: // last year
return (12 - start.Month) + end.Month;
default:
return 12 * (3 - (end.Year - start.Year)) + (12 - start.Month) + end.Month;
}
}
The most precise way is this that return difference in months by fraction :
private double ReturnDiffereceBetweenTwoDatesInMonths(DateTime startDateTime, DateTime endDateTime)
{
double result = 0;
double days = 0;
DateTime currentDateTime = startDateTime;
while (endDateTime > currentDateTime.AddMonths(1))
{
result ++;
currentDateTime = currentDateTime.AddMonths(1);
}
if (endDateTime > currentDateTime)
{
days = endDateTime.Subtract(currentDateTime).TotalDays;
}
return result + days/endDateTime.GetMonthDays;
}
My understanding of the total months difference between 2 dates has an integral and a fractional part (the date matters).
The integral part is the full months difference.
The fractional part, for me, is the difference of the % of the day (to the full days of month) between the starting and ending months.
public static class DateTimeExtensions
{
public static double TotalMonthsDifference(this DateTime from, DateTime to)
{
//Compute full months difference between dates
var fullMonthsDiff = (to.Year - from.Year)*12 + to.Month - from.Month;
//Compute difference between the % of day to full days of each month
var fractionMonthsDiff = ((double)(to.Day-1) / (DateTime.DaysInMonth(to.Year, to.Month)-1)) -
((double)(from.Day-1)/ (DateTime.DaysInMonth(from.Year, from.Month)-1));
return fullMonthsDiff + fractionMonthsDiff;
}
}
With this extension, those are the results:
2/29/2000 TotalMonthsDifference 2/28/2001 => 12
2/28/2000 TotalMonthsDifference 2/28/2001 => 12.035714285714286
01/01/2000 TotalMonthsDifference 01/16/2000 => 0.5
01/31/2000 TotalMonthsDifference 01/01/2000 => -1.0
01/31/2000 TotalMonthsDifference 02/29/2000 => 1.0
01/31/2000 TotalMonthsDifference 02/28/2000 => 0.9642857142857143
01/31/2001 TotalMonthsDifference 02/28/2001 => 1.0
Here is a simple solution that works at least for me. It's probably not the fastest though because it uses the cool DateTime's AddMonth feature in a loop:
public static int GetMonthsDiff(DateTime start, DateTime end)
{
if (start > end)
return GetMonthsDiff(end, start);
int months = 0;
do
{
start = start.AddMonths(1);
if (start > end)
return months;
months++;
}
while (true);
}
This simple static function calculates the fraction of months between two Datetimes, e.g.
1.1. to 31.1. = 1.0
1.4. to 15.4. = 0.5
16.4. to 30.4. = 0.5
1.3. to 1.4. = 1 + 1/30
The function assumes that the first date is smaller than the second date. To deal with negative time intervals one can modify the function easily by introducing a sign and a variable swap at the beginning.
public static double GetDeltaMonths(DateTime t0, DateTime t1)
{
DateTime t = t0;
double months = 0;
while(t<=t1)
{
int daysInMonth = DateTime.DaysInMonth(t.Year, t.Month);
DateTime endOfMonth = new DateTime(t.Year, t.Month, daysInMonth);
int cutDay = endOfMonth <= t1 ? daysInMonth : t1.Day;
months += (cutDay - t.Day + 1) / (double) daysInMonth;
t = new DateTime(t.Year, t.Month, 1).AddMonths(1);
}
return Math.Round(months,2);
}
one line solution
For first, check if both dates are in the current year, if not get months of whole years and then add months from the start and end year.
DateTime dateFrom = new DateTime(2019, 2, 1);
DateTime dateTo = new DateTime(2021, 5, 25);
With the first month
var monthCount = dateFrom.Year != dateTo.Year ? ((dateTo.Year - dateFrom.Year - 1) * 12) + (13 - dateFrom.Month + dateTo.Month) : dateTo.Month - dateFrom.Month + 1;
result = 28
Without first month
monthCount = dateFrom.Year != dateTo.Year ? ((dateTo.Year - dateFrom.Year - 1) * 12) + (12 - dateFrom.Month + dateTo.Month) : dateTo.Month - dateFrom.Month;
result = 27
Public Class ClassDateOperation
Private prop_DifferenceInDay As Integer
Private prop_DifferenceInMonth As Integer
Private prop_DifferenceInYear As Integer
Public Function DayMonthYearFromTwoDate(ByVal DateStart As Date, ByVal DateEnd As Date) As ClassDateOperation
Dim differenceInDay As Integer
Dim differenceInMonth As Integer
Dim differenceInYear As Integer
Dim myDate As Date
DateEnd = DateEnd.AddDays(1)
differenceInYear = DateEnd.Year - DateStart.Year
If DateStart.Month <= DateEnd.Month Then
differenceInMonth = DateEnd.Month - DateStart.Month
Else
differenceInYear -= 1
differenceInMonth = (12 - DateStart.Month) + DateEnd.Month
End If
If DateStart.Day <= DateEnd.Day Then
differenceInDay = DateEnd.Day - DateStart.Day
Else
myDate = CDate("01/" & DateStart.AddMonths(1).Month & "/" & DateStart.Year).AddDays(-1)
If differenceInMonth <> 0 Then
differenceInMonth -= 1
Else
differenceInMonth = 11
differenceInYear -= 1
End If
differenceInDay = myDate.Day - DateStart.Day + DateEnd.Day
End If
prop_DifferenceInDay = differenceInDay
prop_DifferenceInMonth = differenceInMonth
prop_DifferenceInYear = differenceInYear
Return Me
End Function
Public ReadOnly Property DifferenceInDay() As Integer
Get
Return prop_DifferenceInDay
End Get
End Property
Public ReadOnly Property DifferenceInMonth As Integer
Get
Return prop_DifferenceInMonth
End Get
End Property
Public ReadOnly Property DifferenceInYear As Integer
Get
Return prop_DifferenceInYear
End Get
End Property
End Class
This is from my own library, will return the difference of months between two dates.
public static int MonthDiff(DateTime d1, DateTime d2)
{
int retVal = 0;
// Calculate the number of years represented and multiply by 12
// Substract the month number from the total
// Substract the difference of the second month and 12 from the total
retVal = (d1.Year - d2.Year) * 12;
retVal = retVal - d1.Month;
retVal = retVal - (12 - d2.Month);
return retVal;
}
You can have a function something like this.
For Example, from 2012/12/27 to 2012/12/29 becomes 3 days. Likewise, from 2012/12/15 to 2013/01/15 becomes 2 months, because up to 2013/01/14 it's 1 month. from 15th it's 2nd month started.
You can remove the "=" in the second if condition, if you do not want to include both days in the calculation. i.e, from 2012/12/15 to 2013/01/15 is 1 month.
public int GetMonths(DateTime startDate, DateTime endDate)
{
if (startDate > endDate)
{
throw new Exception("Start Date is greater than the End Date");
}
int months = ((endDate.Year * 12) + endDate.Month) - ((startDate.Year * 12) + startDate.Month);
if (endDate.Day >= startDate.Day)
{
months++;
}
return months;
}
you can use the following extension:
Code
public static class Ext
{
#region Public Methods
public static int GetAge(this DateTime #this)
{
var today = DateTime.Today;
return ((((today.Year - #this.Year) * 100) + (today.Month - #this.Month)) * 100 + today.Day - #this.Day) / 10000;
}
public static int DiffMonths(this DateTime #from, DateTime #to)
{
return (((((#to.Year - #from.Year) * 12) + (#to.Month - #from.Month)) * 100 + #to.Day - #from.Day) / 100);
}
public static int DiffYears(this DateTime #from, DateTime #to)
{
return ((((#to.Year - #from.Year) * 100) + (#to.Month - #from.Month)) * 100 + #to.Day - #from.Day) / 10000;
}
#endregion Public Methods
}
Implementation !
int Age;
int years;
int Months;
//Replace your own date
var d1 = new DateTime(2000, 10, 22);
var d2 = new DateTime(2003, 10, 20);
//Age
Age = d1.GetAge();
Age = d2.GetAge();
//positive
years = d1.DiffYears(d2);
Months = d1.DiffMonths(d2);
//negative
years = d2.DiffYears(d1);
Months = d2.DiffMonths(d1);
//Or
Months = Ext.DiffMonths(d1, d2);
years = Ext.DiffYears(d1, d2);
Here's a much more concise solution using VB.Net DateDiff for Year, Month, Day only. You can load the DateDiff library in C# as well.
date1 must be <= date2
VB.NET
Dim date1 = Now.AddDays(-2000)
Dim date2 = Now
Dim diffYears = DateDiff(DateInterval.Year, date1, date2) - If(date1.DayOfYear > date2.DayOfYear, 1, 0)
Dim diffMonths = DateDiff(DateInterval.Month, date1, date2) - diffYears * 12 - If(date1.Day > date2.Day, 1, 0)
Dim diffDays = If(date2.Day >= date1.Day, date2.Day - date1.Day, date2.Day + (Date.DaysInMonth(date1.Year, date1.Month) - date1.Day))
C#
DateTime date1 = Now.AddDays(-2000);
DateTime date2 = Now;
int diffYears = DateDiff(DateInterval.Year, date1, date2) - date1.DayOfYear > date2.DayOfYear ? 1 : 0;
int diffMonths = DateDiff(DateInterval.Month, date1, date2) - diffYears * 12 - date1.Day > date2.Day ? 1 : 0;
int diffDays = date2.Day >= date1.Day ? date2.Day - date1.Day : date2.Day + (System.DateTime.DaysInMonth(date1.Year, date1.Month) - date1.Day);
This is in response to Kirk Woll's answer. I don't have enough reputation points to reply to a comment yet...
I liked Kirk's solution and was going to shamelessly rip it off and use it in my code, but when I looked through it I realized it's way too complicated. Unnecessary switching and looping, and a public constructor that is pointless to use.
Here's my rewrite:
public class DateTimeSpan {
private DateTime _date1;
private DateTime _date2;
private int _years;
private int _months;
private int _days;
private int _hours;
private int _minutes;
private int _seconds;
private int _milliseconds;
public int Years { get { return _years; } }
public int Months { get { return _months; } }
public int Days { get { return _days; } }
public int Hours { get { return _hours; } }
public int Minutes { get { return _minutes; } }
public int Seconds { get { return _seconds; } }
public int Milliseconds { get { return _milliseconds; } }
public DateTimeSpan(DateTime date1, DateTime date2) {
_date1 = (date1 > date2) ? date1 : date2;
_date2 = (date2 < date1) ? date2 : date1;
_years = _date1.Year - _date2.Year;
_months = (_years * 12) + _date1.Month - _date2.Month;
TimeSpan t = (_date2 - _date1);
_days = t.Days;
_hours = t.Hours;
_minutes = t.Minutes;
_seconds = t.Seconds;
_milliseconds = t.Milliseconds;
}
public static DateTimeSpan CompareDates(DateTime date1, DateTime date2) {
return new DateTimeSpan(date1, date2);
}
}
Usage1, pretty much the same:
void Main()
{
DateTime compareTo = DateTime.Parse("8/13/2010 8:33:21 AM");
DateTime now = DateTime.Parse("2/9/2012 10:10:11 AM");
var dateSpan = new DateTimeSpan(compareTo, now);
Console.WriteLine("Years: " + dateSpan.Years);
Console.WriteLine("Months: " + dateSpan.Months);
Console.WriteLine("Days: " + dateSpan.Days);
Console.WriteLine("Hours: " + dateSpan.Hours);
Console.WriteLine("Minutes: " + dateSpan.Minutes);
Console.WriteLine("Seconds: " + dateSpan.Seconds);
Console.WriteLine("Milliseconds: " + dateSpan.Milliseconds);
}
Usage2, similar:
void Main()
{
DateTime compareTo = DateTime.Parse("8/13/2010 8:33:21 AM");
DateTime now = DateTime.Parse("2/9/2012 10:10:11 AM");
Console.WriteLine("Years: " + DateTimeSpan.CompareDates(compareTo, now).Years);
Console.WriteLine("Months: " + DateTimeSpan.CompareDates(compareTo, now).Months);
Console.WriteLine("Days: " + DateTimeSpan.CompareDates(compareTo, now).Days);
Console.WriteLine("Hours: " + DateTimeSpan.CompareDates(compareTo, now).Hours);
Console.WriteLine("Minutes: " + DateTimeSpan.CompareDates(compareTo, now).Minutes);
Console.WriteLine("Seconds: " + DateTimeSpan.CompareDates(compareTo, now).Seconds);
Console.WriteLine("Milliseconds: " + DateTimeSpan.CompareDates(compareTo, now).Milliseconds);
}
In my case it is required to calculate the complete month from the start date to the day prior to this day in the next month or from start to end of month.
Ex: from 1/1/2018 to 31/1/2018 is a complete month
Ex2: from 5/1/2018 to 4/2/2018 is a complete month
so based on this here is my solution:
public static DateTime GetMonthEnd(DateTime StartDate, int MonthsCount = 1)
{
return StartDate.AddMonths(MonthsCount).AddDays(-1);
}
public static Tuple<int, int> CalcPeriod(DateTime StartDate, DateTime EndDate)
{
int MonthsCount = 0;
Tuple<int, int> Period;
while (true)
{
if (GetMonthEnd(StartDate) > EndDate)
break;
else
{
MonthsCount += 1;
StartDate = StartDate.AddMonths(1);
}
}
int RemainingDays = (EndDate - StartDate).Days + 1;
Period = new Tuple<int, int>(MonthsCount, RemainingDays);
return Period;
}
Usage:
Tuple<int, int> Period = CalcPeriod(FromDate, ToDate);
Note: in my case it was required to calculate the remaining days after the complete months so if it's not your case you could ignore the days result or even you could change the method return from tuple to integer.
public static int PayableMonthsInDuration(DateTime StartDate, DateTime EndDate)
{
int sy = StartDate.Year; int sm = StartDate.Month; int count = 0;
do
{
count++;if ((sy == EndDate.Year) && (sm >= EndDate.Month)) { break; }
sm++;if (sm == 13) { sm = 1; sy++; }
} while ((EndDate.Year >= sy) || (EndDate.Month >= sm));
return (count);
}
This solution is for Rental/subscription calculation, where difference doesn't means to be subtraction, it's meant to be the span in within those two dates.
I wrote a function to accomplish this, because the others ways weren't working for me.
public string getEndDate (DateTime startDate,decimal monthCount)
{
int y = startDate.Year;
int m = startDate.Month;
for (decimal i = monthCount; i > 1; i--)
{
m++;
if (m == 12)
{ y++;
m = 1;
}
}
return string.Format("{0}-{1}-{2}", y.ToString(), m.ToString(), startDate.Day.ToString());
}
There are not a lot of clear answers on this because you are always assuming things.
This solution calculates between two dates the months between assuming you want to save the day of month for comparison, (meaning that the day of the month is considered in the calculation)
Example, if you have a date of 30 Jan 2012, 29 Feb 2012 will not be a month but 01 March 2013 will.
It's been tested pretty thoroughly, probably will clean it up later as we use it, but here:
private static int TotalMonthDifference(DateTime dtThis, DateTime dtOther)
{
int intReturn = 0;
bool sameMonth = false;
if (dtOther.Date < dtThis.Date) //used for an error catch in program, returns -1
intReturn--;
int dayOfMonth = dtThis.Day; //captures the month of day for when it adds a month and doesn't have that many days
int daysinMonth = 0; //used to caputre how many days are in the month
while (dtOther.Date > dtThis.Date) //while Other date is still under the other
{
dtThis = dtThis.AddMonths(1); //as we loop, we just keep adding a month for testing
daysinMonth = DateTime.DaysInMonth(dtThis.Year, dtThis.Month); //grabs the days in the current tested month
if (dtThis.Day != dayOfMonth) //Example 30 Jan 2013 will go to 28 Feb when a month is added, so when it goes to march it will be 28th and not 30th
{
if (daysinMonth < dayOfMonth) // uses day in month max if can't set back to day of month
dtThis.AddDays(daysinMonth - dtThis.Day);
else
dtThis.AddDays(dayOfMonth - dtThis.Day);
}
if (((dtOther.Year == dtThis.Year) && (dtOther.Month == dtThis.Month))) //If the loop puts it in the same month and year
{
if (dtOther.Day >= dayOfMonth) //check to see if it is the same day or later to add one to month
intReturn++;
sameMonth = true; //sets this to cancel out of the normal counting of month
}
if ((!sameMonth)&&(dtOther.Date > dtThis.Date))//so as long as it didn't reach the same month (or if i started in the same month, one month ahead, add a month)
intReturn++;
}
return intReturn; //return month
}
Based on the excellent DateTimeSpan work done above, I've normalized the code a bit; this seems to work pretty well:
public class DateTimeSpan
{
private DateTimeSpan() { }
private DateTimeSpan(int years, int months, int days, int hours, int minutes, int seconds, int milliseconds)
{
Years = years;
Months = months;
Days = days;
Hours = hours;
Minutes = minutes;
Seconds = seconds;
Milliseconds = milliseconds;
}
public int Years { get; private set; } = 0;
public int Months { get; private set; } = 0;
public int Days { get; private set; } = 0;
public int Hours { get; private set; } = 0;
public int Minutes { get; private set; } = 0;
public int Seconds { get; private set; } = 0;
public int Milliseconds { get; private set; } = 0;
public static DateTimeSpan CompareDates(DateTime StartDate, DateTime EndDate)
{
if (StartDate.Equals(EndDate)) return new DateTimeSpan();
DateTimeSpan R = new DateTimeSpan();
bool Later;
if (Later = StartDate > EndDate)
{
DateTime D = StartDate;
StartDate = EndDate;
EndDate = D;
}
// Calculate Date Stuff
for (DateTime D = StartDate.AddYears(1); D < EndDate; D = D.AddYears(1), R.Years++) ;
if (R.Years > 0) StartDate = StartDate.AddYears(R.Years);
for (DateTime D = StartDate.AddMonths(1); D < EndDate; D = D.AddMonths(1), R.Months++) ;
if (R.Months > 0) StartDate = StartDate.AddMonths(R.Months);
for (DateTime D = StartDate.AddDays(1); D < EndDate; D = D.AddDays(1), R.Days++) ;
if (R.Days > 0) StartDate = StartDate.AddDays(R.Days);
// Calculate Time Stuff
TimeSpan T1 = EndDate - StartDate;
R.Hours = T1.Hours;
R.Minutes = T1.Minutes;
R.Seconds = T1.Seconds;
R.Milliseconds = T1.Milliseconds;
// Return answer. Negate values if the Start Date was later than the End Date
if (Later)
return new DateTimeSpan(-R.Years, -R.Months, -R.Days, -R.Hours, -R.Minutes, -R.Seconds, -R.Milliseconds);
return R;
}
}
Insane method that counts all days, so super precise
helper class :
public class DaysInMonth
{
public int Days { get; set; }
public int Month { get; set; }
public int Year { get; set; }
public bool Full { get; set; }
}
function:
public static List<DaysInMonth> MonthsDelta(DateTime start, DateTime end)
{
var dates = Enumerable.Range(0, 1 + end.Subtract(start).Days)
.Select(offset => start.AddDays(offset))
.ToArray();
DateTime? prev = null;
int days = 0;
List < DaysInMonth > list = new List<DaysInMonth>();
foreach (DateTime date in dates)
{
if (prev != null)
{
if(date.Month!=prev.GetValueOrDefault().Month)
{
DaysInMonth daysInMonth = new DaysInMonth();
daysInMonth.Days = days;
daysInMonth.Month = prev.GetValueOrDefault().Month;
daysInMonth.Year = prev.GetValueOrDefault().Year;
daysInMonth.Full = DateTime.DaysInMonth(daysInMonth.Year, daysInMonth.Month) == daysInMonth.Days;
list.Add(daysInMonth);
days = 0;
}
}
days++;
prev = date;
}
//------------------ add last
if (days > 0)
{
DaysInMonth daysInMonth = new DaysInMonth();
daysInMonth.Days = days;
daysInMonth.Month = prev.GetValueOrDefault().Month;
daysInMonth.Year = prev.GetValueOrDefault().Year;
daysInMonth.Full = DateTime.DaysInMonth(daysInMonth.Year, daysInMonth.Month) == daysInMonth.Days;
list.Add(daysInMonth);
}
return list;
}

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