Dear all,

I want to get time value out from intersection of two time intervals.

Example:
Main time interval: 09:20:00 - 15:00:00
Time interval 1: 06:00:00 - 14:00:00
Time interval 2: 14:00:00 - 22:00:00

Intersection of main time interval and interval 1 is 04:40:00
Intersection of main time interval and interval 2 is 01:00:00

How to do that in C#?

Thank you!

Regards, Egi

This should work though, if the intervals straddle midnight, then you'll need to specify the date as well as the time:

using System;

class Program
{
    static void Main()
    {
        DateTime mainStart = DateTime.Parse("09:20:00");
        DateTime mainEnd = DateTime.Parse("15:00:00");

        DateTime intervalStart = DateTime.Parse("06:00:00");
        DateTime intervalEnd = DateTime.Parse("14:00:00");

        TimeSpan ts = GetIntersection(mainStart, mainEnd, intervalStart, intervalEnd);
        Console.WriteLine(ts);

        intervalStart = DateTime.Parse("14:00:00");
        intervalEnd = DateTime.Parse("22:00:00");        
        ts = GetIntersection(mainStart, mainEnd, intervalStart, intervalEnd);
        Console.WriteLine(ts);

        Console.ReadLine();       
    }

    public static TimeSpan GetIntersection(DateTime mainStart, DateTime mainEnd, DateTime intervalStart, DateTime intervalEnd)
    {
        if (mainStart >= mainEnd || intervalStart >= intervalEnd)
        {
            return TimeSpan.Zero;
        }
 
        if(intervalStart >= mainEnd || intervalEnd <= mainStart)
        {
            return TimeSpan.Zero;
        }

        if (intervalStart >= mainStart && intervalEnd <= mainEnd)
        {
            return intervalEnd - intervalStart;
        }

        DateTime tempStart = intervalStart;
        DateTime tempEnd = intervalEnd;

        if (intervalStart < mainStart) tempStart = mainStart;
        if (intervalEnd > mainEnd) tempEnd = mainEnd;
        return tempEnd - tempStart;    
    }
}

I've modified the above program so that, if you enter a negative or zero interval, it assumes that the interval must end on the following day i.e. 24 hours should be added:

using System;

class Program
{
    static void Main()
    {
        DateTime mainStart = DateTime.Parse("09:20:00");
        DateTime mainEnd = DateTime.Parse("05:00:00");

        DateTime intervalStart = DateTime.Parse("06:00:00");
        DateTime intervalEnd = DateTime.Parse("05:40:00");

        TimeSpan ts = GetIntersection(mainStart, mainEnd, intervalStart, intervalEnd);
        Console.WriteLine(ts);

        intervalStart = DateTime.Parse("14:00:00");
        intervalEnd = DateTime.Parse("01:00:00");        
        ts = GetIntersection(mainStart, mainEnd, intervalStart, intervalEnd);
        Console.WriteLine(ts);

        Console.ReadLine();       
    }

    public static TimeSpan GetIntersection(DateTime mainStart, DateTime mainEnd, DateTime intervalStart, DateTime intervalEnd)
    {
        if (mainStart >= mainEnd)
        {
            mainEnd += new TimeSpan(24,0,0);
        }

        if (intervalStart >= intervalEnd)
        {
            intervalEnd += new TimeSpan(24,0,0);
        }
    
        if(intervalStart >= mainEnd || intervalEnd <= mainStart)
        {
            return TimeSpan.Zero;
        }

        if (intervalStart >= mainStart && intervalEnd <= mainEnd)
        {
            return intervalEnd - intervalStart;
        }

        DateTime tempStart = intervalStart;
        DateTime tempEnd = intervalEnd;

        if (intervalStart < mainStart) tempStart = mainStart;
        if (intervalEnd > mainEnd) tempEnd = mainEnd;
        return tempEnd - tempStart;    
    }
}

Thank you for very quick response!
I'll try that piece of code later and let u know if this is what i was looking for ...