using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        // creating measurements

        var january = new Month("January");

        january.Measurements.Add(new Measurement { Day = "Day1", Temperature = 22 });

        january.Measurements.Add(new Measurement { Day = "Day2", Temperature = 25 });

        january.Measurements.Add(new Measurement { Day = "Day3", Temperature = 26 });

        january.Measurements.Add(new Measurement { Day = "Day4", Temperature = 18 });

        january.Measurements.Add(new Measurement { Day = "Day5", Temperature = 16 });

        january.Measurements.Add(new Measurement { Day = "Day6", Temperature = 17 });

​

        // finding months by their name

        // using a dictionary will perform this lookup in O(1)

        var months = new Dictionary<string, Month>();

        months.Add(january.Name, january);

​

        var selectedValue = "January"; // DropDownList1.SelectedValue.ToString();

        if (months.ContainsKey(selectedValue)) {

            var selectedMonth = months[selectedValue];

​

            // do calculations for the selected month

            // how the calculations are performed is encapsulated

            var max = selectedMonth.MaxByTemp;

            string averageTemp = string.Format("{0:0.00}", selectedMonth.Average);

​

            // Label1.Text = string.Format(

            Console.WriteLine(selectedMonth.Name + ": Max " + max.Temperature + 

                " (on " + max.Day + ") Avg " +  averageTemp);

        }

        else {

            throw new KeyNotFoundException("Month not found: " + selectedValue);

        }

    }

    // groups measurements for a certain month and does calculations

    public class Month {

​

        public Month(string name) {

            Name = name;

            Measurements = new List<Measurement>();

        }

        // dictionary key

        public string Name { get; private set; }

        // note that the outside only knows we use an ICollection,

        // that we actually use a List in our implementation is hidden from them

        public ICollection<Measurement> Measurements { get; private set;}

        // to answer your original question:

        // LINQ .Min(m => m.Temperature) and .Max() would only return int

        // sorting will allow you to return the full Measurement, including the day

        // runs in O(log(n)), see http://stackoverflow.com/q/3188693/1450855

        public Measurement MinByTemp { get { return Measurements.OrderBy(m => m.Temperature).First(); } }

        public Measurement MaxByTemp { get { return Measurements.OrderBy(m => m.Temperature).Last(); } }

​

        // more LINQ goodness

        public double Average { get { return Measurements.Average(r => r.Temperature); } }   

    }

    public class Measurement {

        public string Day { get; set; }

        public int Temperature { get; set; }

    }

}