How to convert EF List objects to an arrayList of type dateTime

Question

I'm working on a leave application. I need to get the excluded dates and convert it into a dateTime array.

I used the following approach to partially achieve this. I created a Helper folder then added the following class to the folder:

namespace eLeave.Helpers
{
    public class BusinessDaysCalculator
    {
        public int Calculate(DateTime startDate, DateTime endDate, DateTime[] holidays)
        {
            startDate = FixStartDate(startDate);
            endDate = FixEndDate(endDate.Date);

            if (startDate > endDate)
                return 0;
            else
                return CalculateDifference(startDate, endDate, holidays);
        }



        private int CalculateDifference(DateTime startDate, DateTime endDate, DateTime[] holidays)
        {
            int difference = (int)(endDate - startDate).TotalDays;
            int weeks = difference / 7;
            if (endDate.DayOfWeek < startDate.DayOfWeek) weeks++;
            difference -= weeks * 2;
            difference -= HolidayCount(startDate, endDate, holidays);
            return difference + 1;
        }



        private int HolidayCount(DateTime startDate, DateTime endDate, DateTime[] holidays)
        {
            int holidayCount = 0;
            foreach (DateTime holiday in holidays)
            {
                if (HolidayInRange(startDate, endDate, holiday))
                    holidayCount++;
            }
            return holidayCount;
        }



        private DateTime FixStartDate(DateTime date)
        {
            if (date.DayOfWeek == DayOfWeek.Sunday)
                date = date.AddDays(1);
            else if (date.DayOfWeek == DayOfWeek.Saturday)
                date = date.AddDays(2);
            return date.Date;
        }



        private bool HolidayInRange(DateTime startDate, DateTime endDate, DateTime holiday)
        {
            return (holiday >= startDate
                && holiday <= endDate
                && holiday.DayOfWeek != DayOfWeek.Saturday
                && holiday.DayOfWeek != DayOfWeek.Sunday);
        }



        private DateTime FixEndDate(DateTime date)
        {
            if (date.DayOfWeek == DayOfWeek.Sunday)
                date = date.AddDays(-2);
            else if (date.DayOfWeek == DayOfWeek.Saturday)
                date = date.AddDays(-1);
            return date.Date;
        }
    }
}

I instantiated the class like below and passed the excludedDate into it like below:

// Get the Excluded dates
var excludedDates = _context.ExcludedDate.Where(d=>d.ExcludedDates >= StartDate).Where(d=>d.ExcludedDates <= EndDate).ToArray();

BusinessDaysCalculator calc = new BusinessDaysCalculator();
int days = calc.Calculate(StartDate, EndDate, excludedDates);    

The implementation was meant to work but gave errors but when tried with the holidays DateTime Arrray below

   DateTime[] holidays = new DateTime[3];
   holidays[0] = new DateTime(2017, 08, 15);
   holidays[1] = new DateTime(2017, 09, 1);    

I got the leave days with the excluded date in the holiday Array above

I need to get the values of excludedDates and use it with my class to get it to work.

The Errors I got here below:

Error   1   The best overloaded method match for 'eLeave.Helpers.BusinessDaysCalculator.Calculate(System.DateTime, System.DateTime, System.DateTime[])' has some invalid arguments  C:\Apps\WebApplications\eLeave\eLeave\eLeave\Controllers\RequestController.cs   100 32  eLeave


Error   2   Argument 3: cannot convert from 'eLeave.Models.ExcludedDate[]' to 'System.DateTime[]'   C:\Apps\WebApplications\eLeave\eLeave\eLeave\Controllers\RequestController.cs   100 67  eLeave

Model for excluded date are as follows:

public class ExcludedDate
{
    public byte Id { get; set; }
    public DateTime? ExcludedDates { get; set; }
}

Answer 1

Your query is returning an array of your ExcludedDate class which is not type DateTime - you need a .Select() clause to select just the ExcludedDates property of the object.

Change the query to

DateTime[] excludedDates = _context.ExcludedDate
    .Where(d=>d.ExcludedDates >= StartDate && d.ExcludedDates <= EndDate)
    .Select(x => x.ExcludedDates)
    .ToArray();

Note its unclear why your property is nullable (there would be no point having a null value for that property, and the name is a little confusing in relationship to the table name. I would suggest you change it to public DateTime Date { get; set; }