How to count number Holidays between 2 dates C#

Question

How can I count the number of holidays from database between 2 days

I already count the number of business days but how can i minus to week days the number of holidays counted between 2 days.

Assuming that I have a Holidays table with

Halloween 11-01
Christmas 12-25

Dates:

start date = 10-25
end date = 01-30

Answer should be: Business days - Holiday Number between 2 dates ;

Here's my code:

 public static void GetBusinessDays(DateTime startD, DateTime endD)
 {
            double calcBusinessDays =
                1 + ((endD - startD).TotalDays * 5 -
                (startD.DayOfWeek - endD.DayOfWeek) * 2) / 7;

            if (endD.DayOfWeek == DayOfWeek.Saturday) calcBusinessDays--;
            if (startD.DayOfWeek == DayOfWeek.Sunday) calcBusinessDays--;

            MessageBox.Show(" " + calcBusinessDays);
        }

from this link :Calculate the number of business days between two dates?

Button:

 private void button1_Click(object sender, EventArgs e)
        {
            GetBusinessDays(Convert.ToDateTime(metroDateTime1.Value.ToString("yyyy-MM-dd")), Convert.ToDateTime(metroDateTime2.Value.ToString("yyyy-MM-dd")));
        }

PS: I'm new to c#

`metroDateTime1.Value` is already of type `DateTime` – Fabio Sep 30 '18 at 05:27 — Fabio, Sep 30 '18 at 05:27

score 1 · Accepted Answer · edited Jun 10 '19 at 06:19

1

While only

while (Start.Date <= End.Date) 
{ 
    if (Start.DayOfWeek == DayOfWeek.Saturday || Start.DayOfWeek == DayOfWeek.Sunday) 
        holidays++; 
    Start = Start.AddDays(1);
}

Could calculate the holiday count, but the code below is more efficient, as we already know that every 7 days has 2 holiday in it and don't have to go through it and only checking days % 7 (6 days at most) for holidays is enough.

int days = (int)(End - Start).TotalDays + 1;
        int holidays = days / 7 * 2;
        int remain = days % 7;
        DateTime dt = End.AddDays(-remain);
        while (dt.Date <= End.Date)
        {
            if (dt.DayOfWeek == DayOfWeek.Saturday || dt.DayOfWeek == DayOfWeek.Sunday)
                holidays++;
            dt = dt.AddDays(1);
        }
        int year = Start.Year;
        do
        {
            dt = new DateTime(year, 12, 25); //is chritsmass right?
            if (dt >= Start && dt <= End && dt.DayOfWeek!=DayOfWeek.Saturday && dt.DayOfWeek != DayOfWeek.Sunday) holidays++;
            dt = new DateTime(year, 7, 4); // 4th of july
            if (dt >= Start && dt <= End && dt.DayOfWeek!=DayOfWeek.Saturday && dt.DayOfWeek != DayOfWeek.Sunday) holidays++;
            dt = new DateTime(year, 10, 31); // holoween
            if (dt >= Start && dt <= End && dt.DayOfWeek!=DayOfWeek.Saturday && dt.DayOfWeek != DayOfWeek.Sunday) holidays++;
            year++;
        } while (year <= End.Year);
        int businessDays = days - holidays;

Live Demo

edited Jun 10 '19 at 06:19

marc_s

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answered Sep 30 '18 at 05:30

Ashkan Mobayen Khiabani

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`DateTime.AddDays` will not update existed instance - it will return new `DateTime` – Fabio Sep 30 '18 at 05:35
sorry i did't understand what you mean – Kim Ivan Bay-an Sep 30 '18 at 05:36
@Fabio my bad, I had made a mistake. Thanks for mentioning – Ashkan Mobayen Khiabani Sep 30 '18 at 05:37
answer = Working - Holiday Number between 2 dates – Kim Ivan Bay-an Sep 30 '18 at 05:41
@KimIvanBay-an to calculate holidays, we can loop through all days and add to our holidays if day is saturday or sunday, however a week and i mean 7 continous days by week (no matter where to start) of course have 1 saturday and 1 sunday in it. so for example if subtract of the 2 dates are 200 days, we have (200 / 7 = 28 week) and as 200 % 7 = 4 (we have 28 weeks and 4 days). so 2 holidays for each week (28*2) and we loop through last 4 days to find out whether they are saturday or sunday or not. – Ashkan Mobayen Khiabani Sep 30 '18 at 05:42
@KimIvanBay-an and `int bussinessDays = days - holidays;` would give us the business days. – Ashkan Mobayen Khiabani Sep 30 '18 at 05:46
i get that i mean for holidays is like chritsmass , Holoween that is stored in my database the date and month of it. – Kim Ivan Bay-an Sep 30 '18 at 05:47
@KimIvanBay-an I added some code to my answer to cover christmass, holoween and... please check the answer – Ashkan Mobayen Khiabani Sep 30 '18 at 05:58
why it gives me -4 when i set the start to Dec. 23 End at Dec 26 – Kim Ivan Bay-an Sep 30 '18 at 06:15
I executed the code with Dec 23, and dec 26 and got holidays = 1. which year you set for them (i used 2018 for both). by the ways there were typos in my code that i corrected them – Ashkan Mobayen Khiabani Sep 30 '18 at 06:22
@KimIvanBay-an oppsss my bad, instead of `end - start` I was doind `start - end`. i corrected it, please check the [live demo](https://dotnetfiddle.net/1q15om) – Ashkan Mobayen Khiabani Sep 30 '18 at 06:27
ow its working,but i have a stupid question looks like spoon feeding but how can i modify this code to get the holidays date from my table holidays, that has month and date in it? – Kim Ivan Bay-an Sep 30 '18 at 06:32
what is the format in your table? you have month and day in separate fields, or datetime field? – Ashkan Mobayen Khiabani Sep 30 '18 at 06:37
Date time field in format of MM-dd, i found a bug i set Oct. 31 to Nov. 2 it gives me 2 – Kim Ivan Bay-an Sep 30 '18 at 06:40
inside the `do -while` that goes year by year, put another for loop that loops through your holidays from table like: `do { foreach( DateTime x in YourDatesFromTable) { DateTime dt = new DateTime(year, x.Month,x.day); if (dt >= Start && dt <= End) holidays++;}}` – Ashkan Mobayen Khiabani Sep 30 '18 at 06:42
Oct. 31 to Nov. 2, gives 1 holiday, 2 busniess which is correct – Ashkan Mobayen Khiabani Sep 30 '18 at 06:46
again i edited answer (when checking table holidays, we should holiday++ if the date is not saturday or sunday as if they are one of these days the are already counted. – Ashkan Mobayen Khiabani Sep 30 '18 at 06:50
but when i set it Oct.29 to Oct. 31 gives me 1 and when i set to Oct 29 to Nov 1 gives me 2 – Kim Ivan Bay-an Sep 30 '18 at 06:59
what about Leap year sir? – Kim Ivan Bay-an Sep 30 '18 at 08:39

How to count number Holidays between 2 dates C#

1 Answers1