Generics:
As we know C# is a strongly typed language, programmers have to specify the type of an object at the time of writing the program.
"Generics introduce to the .NET Framework the concept of type parameters, which make it possible to design classes and methods that defer the specification of one or more types until the class or method is declared and instantiated by client code."
We can write a generic method for sorting an array of objects, then invoke the generic method separately with an int array, a double array, a string array and so on, to sort each different type of array.
Generic methods enable us to specify, with a single method declaration, a set of related methods. Generic classes enable us to specify, with a single class declaration, a set of related classes. Similarly, generic interfaces enable us to specify, with a single interface declaration, a set of related interfaces. Generics provide compile-time type safety.
They are equivalent. The compiler changes the
query expression into the equivalent Lambda expression before compiling it, so the generated IL is exactly the same.
Example
var result = (from p in objGL
orderby p.Name
select p).ToList()
is exactly the same as
var result = IEnumerable<Genericuselinq> query = objGL.OrderBy(x => x.Name.ToLower()).ToList();
Note that if you write the query expression like this:
var result = (from objGL
orderby p.Name
select p).ToList()
It's converted to:
var result = objGL.orderby ( p => p.Name);
The final call to Select is omitted because it's redundant.
namespace SampleLinq
{
public class Genericuselinq
{
public int Id { get; set; }
public string Name { get; set; }
}
}
private static void LambdaAndLinq()
{
List<Genericuselinq> objGL = new List<Genericuselinq>();
Genericuselinq obj = new Genericuselinq();
obj.Id = 1;
obj.Name = "sriram";
objGL.Add(obj);
obj = new Genericuselinq();
obj.Id = 6;
obj.Name = "arun";
objGL.Add(obj);
obj = new Genericuselinq();
obj.Id = 5;
obj.Name = "malar";
objGL.Add(obj);
obj = new Genericuselinq();
obj.Id = 14;
obj.Name = "peter";
objGL.Add(obj);
obj = new Genericuselinq();
obj.Id = 13;
obj.Name = "kumar";
objGL.Add(obj);
obj = new Genericuselinq();
obj.Id = 123;
obj.Name = "John";
objGL.Add(obj);
IEnumerable<Genericuselinq> query = objGL.OrderBy(x => x.Name.ToLower()).ToList();
Console.WriteLine("lambda expression in c#");
foreach (Genericuselinq word in query)
{
Console.WriteLine("Id = " + word.Id + " Name =
" + word.Name);
}
Console.WriteLine("Linq in C#");
List<Genericuselinq> sortedProducts = (from p in objGL
orderby
p.Name
select p).ToList();
foreach (var w in sortedProducts)
{
Console.WriteLine("Id : " + w.Id + " Name :
" + w.Name);
}
Console.Read();
}
