In previous article, I had discussed about Extension methods. Now, we will look into implementation of Extension Methods in LINQ. I designed this application in Visual Studio 2008 using Console Applications.

Introduction to LINQ:

LINQ is a new technology that will allow writing Queries in C# itself. It's based on Query Expressions. Query Expressions uses declarative query syntax. It means, we will just specify what we want without bothering about specification of how to get it. By using Query Expressions, we can write queries in C#, which are type safe. LINQ makes a Query a built-in construct of C# just like a class or struct. LINQ uses Extension Methods in its internal implementation of Query Operators like GroupBy, OrderBy etc.

Steps to understand LINQ's Extension Methods:

           var sortedMarks = marks.OrderBy(m => m);
            foreach (var mark in sortedMarks)
            {
                Console.WriteLine(mark);
            }

Above statements, will sort the list by using Extension Method OrderBy present in System.Linq namespace and having lambda expression as a parameter.

Internal Implementation:

If we disassemble this code, we can see the call to extension method will be like this:

Call int32 [System.Core]System.Linq.Enumerable::Max(class [mscorlib]System.Collections.Generic.IEnumerable`1<int32>)

Summary:

So, LINQ uses Extension Methods in its Query operators like OrderBy, GroupBy etc.

I am attaching the code for reference. I hope this will be useful for all.