using System;

public class Program

{

    public static void Main()

    {

        var start = new DateTime(1, 1, 1, 9, 0, 0);

        var end = new DateTime(1, 1, 1, 17, 0, 0);

        Console.WriteLine("{0} - Too early",                TimeBetween(new DateTime(2014, 1, 1, 08, 59, 59, 999), start, end));

        Console.WriteLine("{0} - On start time exclusive",  TimeBetween(new DateTime(2014, 1, 1, 09, 00, 00, 000), start, end, false));

        Console.WriteLine("{0} - On start time inclusive",  TimeBetween(new DateTime(2014, 1, 1, 09, 00, 00, 000), start, end));

        Console.WriteLine("{0} - After start time",         TimeBetween(new DateTime(2014, 1, 1, 09, 00, 00, 001), start, end));        

        Console.WriteLine("{0} - Before end time",          TimeBetween(new DateTime(2014, 1, 1, 16, 59, 59, 999), start, end));

        Console.WriteLine("{0} - On end time inclusive",    TimeBetween(new DateTime(2014, 1, 1, 17, 00, 00, 000), start, end));

        Console.WriteLine("{0} - On end time exclusive",    TimeBetween(new DateTime(2014, 1, 1, 17, 00, 00, 000), start, end, false));

        Console.WriteLine("{0} - Too late",                 TimeBetween(new DateTime(2014, 1, 1, 17, 00, 00, 001), start, end));

    }

    public static bool TimeBetween(DateTime check, DateTime start, DateTime end, bool inclusive = true)

    {

        var from = new DateTime(check.Year, check.Month, check.Day, start.Hour, start.Minute, start.Second, start.Millisecond);

        var to = new DateTime(check.Year, check.Month, check.Day, end.Hour, end.Minute, end.Second, end.Millisecond);

        if (inclusive)

            return from <= check && to >= check;

        return from < check && to > check;

    }

}