LINQ To Objects

 

• LINQ to Objects refer to the use of LINQ queries with any IEnumerable or IEnumerable<T> collection.
• LINQ to query any enumerable collections such as List<T>, Array, or Dictionary<TKey, TValue>
• LINQ to Objects represents a new approach to collections. In older way, you had to write complex foreach loops that specified how to retrieve data from a collection.
•  LINQ queries offer three main advantages over traditional foreach loops:

1. They are more concise and readable, especially when filtering multiple conditions.
2. They provide powerful filtering, ordering, and grouping capabilities with a minimum of application code.
3. They can be ported to other data sources with little or no modification.

How to: Query an ArrayList with LINQ

LINQ to query non-generic IEnumerable collections such as ArrayList, you must explicitly declare the type of the range variable to reflect the specific type of the objects in the collection.

Here I have taken Cricket 's Player class to understand the Linq to Object.

Player contains single properties FirstName,LastName,Country and Multivalue Properties like Scores.List of batsman who have scrored more than 50 runs in their First Match

public class Player

   {

       public string FirstName { get; set; }

       public string LastName { get; set; }

       public string Country { get; set; }

       public int[] Scores { get; set; }

       public int ManOfTheSeries { get; set; }

   }

   class Program

   {

       static void Main(string[] args)

       {

           IList<Player> playerList = new List<Player>()

           {

               new Player

               {

                   FirstName = "Sachin",

                   LastName = "Tendulkar",

                   Country= "India",

                   Scores = new int[] { 200, 190, 170,150  }

               },

               new Player

               {

                   FirstName = "Ricky",

                   LastName = "Ponting",

                   Country = "Australia",

                   Scores = new int[] { 180, 84, 70, 142 }

               },

               new Player

               {

                   FirstName = "Kumar",

                   LastName = "Sangakara",

                   Country = "Sri Lanka",

                   Scores = new int[] { 5, 80, 5, 39 }

               },

               new Player

               {

                   FirstName = "Hashim",

                   LastName = "Amla",

                   Country = "South Africa",

                   Scores = new int[] { 88, 94, 65, 91 }

               },

               new Player

               {

                   FirstName = "Mahela",

                   LastName = "Jayawardene",

                   Country = "Sri Lanka",

                   Scores = new int[] { 97, 89, 85, 82 }

               }

           };

           var query = from Player player in playerList

                       where player.Scores[0] >50

                       select player;

           Console.WriteLine("List of batsman who have scrored more than 50 runs in their First Match");

           foreach (Player s in query)

               Console.WriteLine(s.FirstName +" " + s.LastName + ": " + s.Scores[0]);

            Console.WriteLine("Press any key to exit.");

           Console.ReadKey();

       } 

       }

Output
Sachin Tendulkar: 200
Ricky Ponting: 180
Hashim Amla: 88
Mahela Jayawardene: 97
Press any key to exit.

To get same output with query operator,

Replace above query part with below code.

Console.WriteLine("FILTER- List of batsman who have scrored more than 50 runs in their First Match");

          var queryFilter = playerList

                           .Where(a => a.Scores[0] > 50)

                           .Select(a => a);

 Linq And String

http://msdn.microsoft.com/en-us/library/bb397915.aspx

LINQ and File Directories

http://msdn.microsoft.com/en-us/library/bb397911.aspx

LINQ and Reflection

http://msdn.microsoft.com/en-us/library/bb397929.aspx

How to: Add Custom Methods for LINQ Queries

http://msdn.microsoft.com/en-us/library/cc981895.aspx