using System;

                using System.Collections.Generic;

    using System.Linq;

​

public class Program

{

    private static DateTimeOffset Now = DateTimeOffset.Now.Date;

    public static void Main()

    {

        var test1 = new Test{Date = Now, Count = 1};

        var test2 = new Test{Date = Now.AddDays(-3), Count = 2};

        var test3 = new Test{Date = Now.AddDays(-4), Count = 3};

        var list = new SortedSet<Test>();

        list.Add(test1);

        list.Add(test2);

        list.Add(test3);

        var abd = new TestGroup{

            DateAndValue = list

        };

        abd.FillInMissingDays(Now.AddDays(-10),Now.AddDays(10));

        var min = list.Min;

        Console.WriteLine("Min, {0}",min);

        foreach(var l in abd.DateAndValue)

        {

            Console.WriteLine(l);

        }

    }

    public class TestGroup

    {

        public SortedSet<Test> DateAndValue { get; set; }

​

        /// <summary>

        /// Fill in missing dates with a value of zero.  This assumes

        /// that the data points will be days, this may not be true in all cases

        /// </summary>

        public void FillInMissingDays(DateTimeOffset startDate, DateTimeOffset endDate)

        {

            var date = startDate;

            var empties = Enumerable.Range(0, endDate.Subtract(startDate).Days)

                .Select(i => date.AddDays(i))

                .Select(d => new Test{Count = 0, Date = d});

​

            DateAndValue.UnionWith(empties);

        }

    }

    public class Test : IComparable<Test>, IEquatable<Test>

    {

        public DateTimeOffset Date {get; set;}

        public long Count {get; set;}

                public int CompareTo(Test other)

        {

            return Date.CompareTo(other.Date);

        }

​

        public bool Equals(Test other)

        {

            return Date == other.Date && Count == other.Count;

        }

        public override string ToString()

        {

            return string.Format("{0} {1}", Date, Count);

        }

    }

}