.Net Generics

Introduction

Generics are a new feature in version 2.0 of the C# language and the common language runtime (CLR)

When you use generics, you are creating classes or methods that use a generic type, rather than a specific type. For example, rather than creating a type-specific, you could create a reusable List class using generics.

How is that different from the ArrayList class?

The System.Collection.ArrayList can be used with any objectn, but no type checking is done when objects are passed to methods. You have to manually cast objects back to our type when retrieving; which makes the code harder.

Using the code

I have a Strongly Typed Class named "StudentList" and Generics Class named "MyCustomList" and a sample class named "Student".

"StudentList" class can accepts only Type of Student Objects for its Methods.

But "MyCustomList" Class can Accept any Type u specifying in "T"

Consider the class Student

Student dhas = new Student("Manick", "Dhas", 22);
Student raj = new Student("Sundar", "Raj", 32);

///Using a custom strongly typed StudentList

StudentList mc = new StudentList();
mc.Add(dhas);
mc.Add(raj);

Response.Write("Using a custom strongly typed StudentList
");
foreach (Student s in mc)
{
Response.Write("First Name : " + s.FirstName + "
");
Response.Write("Last Name : " + s.LastName + "
");
Response.Write("Age : " + s.Age + "

");
}
We can use MyCustomList like..

///Creating a list of Student objects using my custom generics

MyCustomList student = new MyCustomList();
student.Add(dhas);
student.Add(raj);

Response.Write("
Using a list of Student objects using my custom generics
");
foreach (Student s in student)
{
Response.Write("First Name : " + s.FirstName + "
");
Response.Write("Last Name : " + s.LastName + "
");
Response.Write("Age : " + s.Age + "

");
}

///Creating a list of Student objects using my custom generics

MyCustomList intlist = new MyCustomList();
intlist.Add(1);
intlist.Add(2);

Response.Write("
Using a list of String values using my custom generics
");
foreach (int i in intlist)
{
Response.Write("Index : " + i.ToString() + "
");
}

///Creating a list of Student objects using my custom generics

MyCustomList strlist = new MyCustomList();
strlist.Add("One");
strlist.Add("Two");

Response.Write("
Using a list of int values using my custom generics
");
foreach (string str in strlist)
{
Response.Write("Index : " + str + "
");
}