using System;

public class Program

{

    public static void Main()

    {

        DateTime borneMin, borneMax = new DateTime();

        //int monthFrom = 3; int monthTo = 7; // 3/1/2019 12:00:00 AM -- 7/31/2019 12:00:00 AM

        //int monthTo = 9; int monthFrom = 12; // 12/1/2018 12:00:00 AM -- 9/30/2019 12:00:00 AM

        //int monthTo = 3; int monthFrom = 6; // 6/1/2019 12:00:00 AM -- 3/31/2019 12:00:00 AM

        // test variable moisDebut / moisFin

        int monthTo = 7;

        int monthFrom = 9;

        // Periode Standard 2018/2019

        //DateTime[] periodDateTime = new [] {new DateTime(2018,9,3), new DateTime(2019, 07, 6)};

        DateTime[] periodDateTime = new [] {new DateTime(2019,9,2), new DateTime(2020, 07, 3)};

​

        int periodMonthMin = periodDateTime[0].Month;

        int periodYearMin = periodDateTime[0].Year;

        DateTime dateMin = periodDateTime[0];

​

        int periodMonthMax = periodDateTime[1].Month;

        int periodYearMax = periodDateTime[1].Year;

        DateTime dateMax = periodDateTime[1];

​

        // BorneMIN

        //borneMin = (monthFrom < periodMonthMin) ? new DateTime(periodYearMax, monthFrom, 1) : new DateTime(periodYearMin, monthFrom, 1);

        if(monthFrom < periodMonthMin)

        {

            borneMin = new DateTime(periodYearMax, monthFrom, 1);

        } else if (monthFrom == periodMonthMin)

        {

            borneMin = dateMin;

        } else 

        {

            borneMin = new DateTime(periodYearMin, monthFrom, 1);

        }

​

        int maxDayInMonth = DateTime.DaysInMonth(periodYearMax, periodMonthMax);

​

        // BorneMAX

        if (monthTo < periodMonthMax)

        {

            maxDayInMonth = DateTime.DaysInMonth(periodYearMax, monthTo);

            borneMax = new DateTime(periodYearMax, monthTo, maxDayInMonth);

        } else

        {

            borneMax = dateMax;

        }

​

        Console.Write(borneMin.ToString() +" -- "+ borneMax.ToString());

    }

}