AddBusinessDays et GetBusinessDays

Question

Je dois trouver 2 implémentations complètes et élégantes de

public static DateTime AddBusinessDays(this DateTime date, int days)
{
 // code here
}

and 

public static int GetBusinessDays(this DateTime start, DateTime end)
{
 // code here
}

O(1) préférable (pas de boucles).

EDIT : Par jours ouvrables, j'entends les jours de travail (lundi, mardi, mercredi, jeudi, vendredi). Pas de jours fériés, sauf les week-ends.

J'ai déjà des solutions peu élégantes qui semblent fonctionner, mais je me demande s'il existe des moyens élégants de le faire. Merci

---

Voici ce que j'ai écrit jusqu'à présent. Il fonctionne dans tous les cas et fait aussi les négatifs. J'ai toujours besoin d'une implémentation de GetBusinessDays

public static DateTime AddBusinessDays(this DateTime startDate,
                                         int businessDays)
{
    int direction = Math.Sign(businessDays);
    if(direction == 1)
    {
        if(startDate.DayOfWeek == DayOfWeek.Saturday)
        {
            startDate = startDate.AddDays(2);
            businessDays = businessDays - 1;
        }
        else if(startDate.DayOfWeek == DayOfWeek.Sunday)
        {
            startDate = startDate.AddDays(1);
            businessDays = businessDays - 1;
        }
    }
    else
    {
        if(startDate.DayOfWeek == DayOfWeek.Saturday)
        {
            startDate = startDate.AddDays(-1);
            businessDays = businessDays + 1;
        }
        else if(startDate.DayOfWeek == DayOfWeek.Sunday)
        {
            startDate = startDate.AddDays(-2);
            businessDays = businessDays + 1;
        }
    }

    int initialDayOfWeek = (int)startDate.DayOfWeek;

    int weeksBase = Math.Abs(businessDays / 5);
    int addDays = Math.Abs(businessDays % 5);

    if((direction == 1 && addDays + initialDayOfWeek > 5) ||
         (direction == -1 && addDays >= initialDayOfWeek))
    {
        addDays += 2;
    }

    int totalDays = (weeksBase * 7) + addDays;
    return startDate.AddDays(totalDays * direction);
}

Answer 1

Dernière tentative pour votre première fonction :

public static DateTime AddBusinessDays(DateTime date, int days)
{
    if (days < 0)
    {
        throw new ArgumentException("days cannot be negative", "days");
    }

    if (days == 0) return date;

    if (date.DayOfWeek == DayOfWeek.Saturday)
    {
        date = date.AddDays(2);
        days -= 1;
    }
    else if (date.DayOfWeek == DayOfWeek.Sunday)
    {
        date = date.AddDays(1);
        days -= 1;
    }

    date = date.AddDays(days / 5 * 7);
    int extraDays = days % 5;

    if ((int)date.DayOfWeek + extraDays > 5)
    {
        extraDays += 2;
    }

    return date.AddDays(extraDays);

}

La deuxième fonction, GetBusinessDays, peut être mise en œuvre comme suit :

public static int GetBusinessDays(DateTime start, DateTime end)
{
    if (start.DayOfWeek == DayOfWeek.Saturday)
    {
        start = start.AddDays(2);
    }
    else if (start.DayOfWeek == DayOfWeek.Sunday)
    {
        start = start.AddDays(1);
    }

    if (end.DayOfWeek == DayOfWeek.Saturday)
    {
        end = end.AddDays(-1);
    }
    else if (end.DayOfWeek == DayOfWeek.Sunday)
    {
        end = end.AddDays(-2);
    }

    int diff = (int)end.Subtract(start).TotalDays;

    int result = diff / 7 * 5 + diff % 7;

    if (end.DayOfWeek < start.DayOfWeek)
    {
        return result - 2;
    }
    else{
        return result;
    }
}

Answer 2

En utilisant DateTime fluide :

var now = DateTime.Now;
var dateTime1 = now.AddBusinessDays(3);
var dateTime2 = now.SubtractBusinessDays(5);

Le code interne est le suivant

    /// <summary>
    /// Adds the given number of business days to the <see cref="DateTime"/>.
    /// </summary>
    /// <param name="current">The date to be changed.</param>
    /// <param name="days">Number of business days to be added.</param>
    /// <returns>A <see cref="DateTime"/> increased by a given number of business days.</returns>
    public static DateTime AddBusinessDays(this DateTime current, int days)
    {
        var sign = Math.Sign(days);
        var unsignedDays = Math.Abs(days);
        for (var i = 0; i < unsignedDays; i++)
        {
            do
            {
                current = current.AddDays(sign);
            }
            while (current.DayOfWeek == DayOfWeek.Saturday ||
                current.DayOfWeek == DayOfWeek.Sunday);
        }
        return current;
    }

    /// <summary>
    /// Subtracts the given number of business days to the <see cref="DateTime"/>.
    /// </summary>
    /// <param name="current">The date to be changed.</param>
    /// <param name="days">Number of business days to be subtracted.</param>
    /// <returns>A <see cref="DateTime"/> increased by a given number of business days.</returns>
    public static DateTime SubtractBusinessDays(this DateTime current, int days)
    {
        return AddBusinessDays(current, -days);
    }

Answer 3

J'ai créé une extension qui vous permet d'ajouter ou de soustraire des jours ouvrables. Utilisez un nombre négatif de businessDays pour soustraire. Je pense que c'est une solution assez élégante. Elle semble fonctionner dans tous les cas.

namespace Extensions.DateTime
{
    public static class BusinessDays
    {
        public static System.DateTime AddBusinessDays(this System.DateTime source, int businessDays)
        {
            var dayOfWeek = businessDays < 0
                                ? ((int)source.DayOfWeek - 12) % 7
                                : ((int)source.DayOfWeek + 6) % 7;

            switch (dayOfWeek)
            {
                case 6:
                    businessDays--;
                    break;
                case -6:
                    businessDays++;
                    break;
            }

            return source.AddDays(businessDays + ((businessDays + dayOfWeek) / 5) * 2);
        }
    }
}

Exemple :

using System;
using System.Windows.Forms;
using Extensions.DateTime;

namespace AddBusinessDaysTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            label1.Text = DateTime.Now.AddBusinessDays(5).ToString();
            label2.Text = DateTime.Now.AddBusinessDays(-36).ToString();
        }
    }
}

Answer 4

Avec l'internationalisation, c'est difficile. Comme mentionné dans d'autres fils de discussion ici sur SOF, les jours fériés diffèrent certainement d'un pays à l'autre et même d'une province à l'autre. La plupart des gouvernements ne programment pas leurs vacances plus de cinq ans ou plus.

Answer 5

public static DateTime AddBusinessDays(this DateTime date, int days)
{
    date = date.AddDays((days / 5) * 7);

    int remainder = days % 5;

    switch (date.DayOfWeek)
    {
        case DayOfWeek.Tuesday:
            if (remainder > 3) date = date.AddDays(2);
            break;
        case DayOfWeek.Wednesday:
            if (remainder > 2) date = date.AddDays(2);
            break;
        case DayOfWeek.Thursday:
            if (remainder > 1) date = date.AddDays(2);
            break;
        case DayOfWeek.Friday:
            if (remainder > 0) date = date.AddDays(2);
            break;
        case DayOfWeek.Saturday:
            if (days > 0) date = date.AddDays((remainder == 0) ? 2 : 1);
            break;
        case DayOfWeek.Sunday:
            if (days > 0) date = date.AddDays((remainder == 0) ? 1 : 0);
            break;
        default:  // monday
            break;
    }

    return date.AddDays(remainder);
}