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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;
}
}

How to calculate WeekEnds in minutes inbetween the two given dates by considering the time also

I have two fields startdate and enddate where I need to calculate how many weekends in between those two dates and show them in minutes. For example start date is 01/11/2019 00:00:00 and end date as 03/11/2019 12:00:00, I should get the output in total Saturday and partial Sunday as 1.5 days weekend in between the given dates
I tried the following code which is not calculating the time on weekends with given scenario
public int CountOfWeekEnds(DateTime startDate, DateTime endDate)
{
int 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.Minute > 0)
{
weekEndCount += 1;
}
}
}
return weekEndCount;
}
Showing output as 2 days of weekend instead of 1.5 days in between the dates. Please suggest how I achieve this

If I understand correctly, by weekends you mean both saturdayand sunday.
I use this code to compute how many DayOfWeek exists between two dates.
public static int CountOfWeekEnds(DateTime start, DateTime end) {
return CountDays(DayOfWeek.Saturday, start, end) + CountDays(DayOfWeek.Sunday, start, end);
}
public static int CountDays(DayOfWeek day, DateTime start, DateTime end)
{
TimeSpan ts = end - start; // Total duration
int count = (int)Math.Floor(ts.TotalDays / 7); // Number of whole weeks
int remainder = (int)(ts.TotalDays % 7); // Number of remaining days
int sinceLastDay = end.DayOfWeek - day; // Number of days since last [day]
if (sinceLastDay < 0) sinceLastDay += 7; // Adjust for negative days since last [day]
// If the days in excess of an even week are greater than or equal to the number days since the last [day], then count this one, too.
if (remainder >= sinceLastDay) count++;
return count;
}
Reference

There are a few things you should change to make this work:
Since we want to return the number of weekend days as a decimal, we need to change our return type to something that represents that, like a double.
Then, when we calculate our days, we need to get the fraction of the day by dividing the hours by 24. In my example below, I went even further and calculated the fraction of days based on the number of Ticks instead of the Hours.
And finally, when we add days, we should use only the Date part of the result so that the time is set to midnight, except for the very last day, where we want to use the specified time.
For example:
public static double GetWeekendDaysCount(DateTime start, DateTime end)
{
if (start == end) return 0;
if (start > end)
{
DateTime temp = start;
start = end;
end = temp;
}
double weekendDays = 0;
var current = start;
// To be super accurate, we can calculate based on Ticks instead of hours
var ticksInADay = (double)TimeSpan.FromDays(1).Ticks;
while (current <= end)
{
if (current.DayOfWeek == DayOfWeek.Saturday ||
current.DayOfWeek == DayOfWeek.Sunday)
{
// If the time is midnight, count it as one day,
// otherwise add a fraction of a day
weekendDays += current.TimeOfDay > TimeSpan.Zero
? current.TimeOfDay.Ticks / ticksInADay
: 1;
}
// Add a day and set the time to midnight by using 'Date'
current = current.AddDays(1).Date;
// Unless we're on the last day, then we want
// to use the TimeOfDay that was specified
if (current == end.Date) current = end;
}
return weekendDays;
}

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.

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

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.

Calculate difference between two dates (number of days)?

I see that this question has been answered for Java, JavaScript, and PHP, but not C#. So, how might one calculate the number of days between two dates in C#?

Assuming StartDate and EndDate are of type DateTime:
(EndDate - StartDate).TotalDays

The top answer is correct, however if you would like only WHOLE days as an int and are happy to forgo the time component of the date then consider:
(EndDate.Date - StartDate.Date).Days
Again assuming StartDate and EndDate are of type DateTime.

Use TimeSpan object which is the result of date substraction:
DateTime d1;
DateTime d2;
return (d1 - d2).TotalDays;

I think this will do what you want:
DateTime d1 = DateTime.Now;
DateTime d2 = DateTime.Now.AddDays(-1);
TimeSpan t = d1 - d2;
double NrOfDays = t.TotalDays;

DateTime xmas = new DateTime(2009, 12, 25);
double daysUntilChristmas = xmas.Subtract(DateTime.Today).TotalDays;

// Difference in days, hours, and minutes.
TimeSpan ts = EndDate - StartDate;
// Difference in days.
int differenceInDays = ts.Days; // This is in int
double differenceInDays= ts.TotalDays; // This is in double
// Difference in Hours.
int differenceInHours = ts.Hours; // This is in int
double differenceInHours= ts.TotalHours; // This is in double
// Difference in Minutes.
int differenceInMinutes = ts.Minutes; // This is in int
double differenceInMinutes= ts.TotalMinutes; // This is in double
You can also get the difference in seconds, milliseconds and ticks.

In case someone wants numer of whole days as a double (a, b of type DateTime):
(a.Date - b.Date).TotalDays

There often is a debate on time (hours) when it comes to counting days between two dates. The responses to the question and their comments show no exception.
Considering StartDate and EndDate are of type DateTime: if performance is not a concern, I would strongly recommend documenting your calculation through intermediate conversions. For example, (EndDate - StartDate).Days is unintuitive because rounding will depend on the hour component of StartDate and EndDate.
If you want the duration in days to include fractions of days, then as already suggested
use (EndDate - StartDate).TotalDays.
If you want the duration to reflect
the distance between two days, then use (EndDate.Date - StartDate.Date).Days
If you want the duration to reflect the
duration between the morning of the start date, and the evening of
the end date (what you typically see in project management software), then use
(EndDate.Date - StartDate.Date).Days + 1

You can try this
EndDate.Date.Subtract(DateTime.Now.Date).Days

Using a timespan would solve the problems as it has many attributes:
DateTime strt_date = DateTime.Now;
DateTime end_date = Convert.ToDateTime("10/1/2017 23:59:59");
//DateTime add_days = end_date.AddDays(1);
TimeSpan nod = (end_date - strt_date);
Console.WriteLine(strt_date + "" + end_date + "" + "" + nod.TotalHours + "");
Console.ReadKey();

For a and b as two DateTime types:
DateTime d = DateTime.Now;
DateTime c = DateTime.Now;
c = d.AddDays(145);
string cc;
Console.WriteLine(d);
Console.WriteLine(c);
var t = (c - d).Days;
Console.WriteLine(t);
cc = Console.ReadLine();

For beginners like me that will stumble upon this tiny problem, in a simple line, with sample conversion to int:
int totalDays = Convert.ToInt32((DateTime.UtcNow.Date - myDateTime.Date).TotalDays);
This calculates the total days from today (DateTime.UtcNow.Date) to a desired date (myDateTime.Date).
If myDateTime is yesterday, or older date than today, this will give a positive (+) integer result.
On the other side, if the myDateTime is tomorrow or on the future date, this will give a negative (-) integer result due to rules of addition.
Happy coding! ^_^

First declare a class that will return later:
public void date()
{
Datetime startdate;
Datetime enddate;
Timespan remaindate;
startdate = DateTime.Parse(txtstartdate.Text).Date;
enddate = DateTime.Parse(txtenddate.Text).Date;
remaindate = enddate - startdate;
if (remaindate != null)
{
lblmsg.Text = "you have left with " + remaindate.TotalDays + "days.";
}
else
{
lblmsg.Text = "correct your code again.";
}
}
protected void btncal_Click(object sender, EventArgs e)
{
date();
}
Use a button control to call the above class. Here is an example:

You can use the code below:
int DateDifInSecond = EndDate.Subtract(StartDate).TotalSeconds

Get the difference between the two dates and then get the days from:
int total_days = (EndDate - StartDate).TotalDays

try this truly worked Get actual days diff. date format is "dd/MM/yyyy"
string[] d1 = txtFromDate.Values.Split('/');
string[] d2 = txtToDate.Values.Split('/');
DateTime FrmDt = new DateTime(Convert.ToInt32(d1[2]), Convert.ToInt32(d1[1]), Convert.ToInt32(d1[0]));
DateTime ToDt = new DateTime(Convert.ToInt32(d2[2]), Convert.ToInt32(d2[1]), Convert.ToInt32(d2[0]));
TimeSpan TDiff = ToDt.Subtract(FrmDt);
String DaysDiff = TDiff.TotalDays.ToString();

protected void Calendar1_SelectionChanged(object sender, EventArgs e)
{
DateTime d = Calendar1.SelectedDate;
// int a;
TextBox2.Text = d.ToShortDateString();
string s = Convert.ToDateTime(TextBox2.Text).ToShortDateString();
string s1 = Convert.ToDateTime(Label7.Text).ToShortDateString();
DateTime dt = Convert.ToDateTime(s).Date;
DateTime dt1 = Convert.ToDateTime(s1).Date;
if (dt <= dt1)
{
Response.Write("<script>alert(' Not a valid Date to extend warranty')</script>");
}
else
{
string diff = dt.Subtract(dt1).ToString();
Response.Write(diff);
Label18.Text = diff;
Session["diff"] = Label18.Text;
}
}