IDictionary<DateTime, Double> get(string ticker, string type, DateTime from, DateTime To);

Dictionary is a collection with key and value. The function get(string ticker, string type, DateTime from, DateTime To) just gets a dictionary with double values mapped with date time; IDictionary it is an interface. You could use it if you want to create dictionary by yourself with specific logic in it. What you should to do is just inherit IDictionary and do like in my sample. In this sample you see the implementation and you can use it when you exactly know your key and value object types. The Entry class is like a mapper to map your key with assigned value. Don't use this sample in real it just for your understanding. And you should read the article in msdn: http://msdn.microsoft.com/en-us/library/s4ys34ea.aspx from Suthish Nair for better understanding.

 

        public class SmallDictionary : IDictionary<DateTime, Double>

        {

            private class Entry

            {

                public DateTime Key { set; get; }

                public Double Value { set; get; }

 

                public Entry(DateTime key, Double value)

                {

                    this.Key = key;

                    this.Value = value;

                }

            }

 

            private List<Entry> entries = new List<Entry>();

 

            public void Add(DateTime key, double value)

            {

                entries.Add(new Entry(key, value));

            }

 

            public double this[DateTime key]

            {

                get

                {

                    double result = 0;

                    Entry entry = FindEntry(key);

 

                    if (entry != null)

                    {

                        result = entry.Value;

                    }

                    else

                    {

                        throw new IndexOutOfRangeException("Key not found!");

                    }

 

                    return result;

                }

                set

                {

                    Entry entry = FindEntry(key);

                    entry.Value = value;

                }

            }

 

            private Entry FindEntry(DateTime key)

            {

                Entry resultEntry = null;

 

                foreach (var entiry in entries)

                {

                    if (entiry.Key == key)

                    {

                        resultEntry = entiry;

                        break;

                    }

                }

                return resultEntry;

            }

            // additional implementation goes here

            ....................

        }

 

 

        public static void Main()

        {

            SmallDictionary myDictionary = new SmallDictionary();

 

            DateTime firstValueChangeDateTime = DateTime.Today;

            DateTime secondValueChangeDateTime = firstValueChangeDateTime.AddHours(1);

 

            // You can add items to to dictionary

 

            myDictionary.Add(firstValueChangeDateTime, 50);

            myDictionary.Add(secondValueChangeDateTime, 60);

 

            // You can get items from dictionary

 

            Console.WriteLine("Second: {0}", myDictionary[secondValueChangeDateTime]);

            Console.WriteLine("First: {0}", myDictionary[firstValueChangeDateTime]);

 

 

            // You can cange value by key

 

            myDictionary[secondValueChangeDateTime] = 500;

            myDictionary[firstValueChangeDateTime] = 800;

 

            // You can get items from dictionary

 

            Console.WriteLine("Second: {0}", myDictionary[secondValueChangeDateTime]);

            Console.WriteLine("First: {0}", myDictionary[firstValueChangeDateTime]);

 

            try

            {

                Console.WriteLine("First: {0}", myDictionary[DateTime.Now]);

            }

            catch(Exception exc)

            {

                Console.WriteLine(exc);

            }

 

            Console.ReadKey();

        }