Generics are a way of ensuring Type Safety at Compile time in C#.
Example- Pre-Generics:
class Person
{
string name;
string lastname;
public Person(string _name ) { this.name = _name; }
}
class ClientCode
{
public static void Main()
{
//create a list of person
ArrayList personList = new ArrayList();
Person p1 = new Person("John");
Person p2 = new Person("Ram");
personList.Add(p1);
personList.Add(p2);
// BUT, someone can do something like:
// ArrayList does not stop adding another type of object into it
object q = new object();
personList.Add(q);
// while accessing personlist
foreach(object obj in personlist)
{
Person p = obj as Person;
// do something, for person
// But it will fail for last item in list 'q' since its is not person.
}
}
}
Example- Post-Generics:
class ClientCode
{
public static void Main()
{
//create a list of person
List personList = new List();
Person p1 = new Person("John");
Person p2 = new Person("Ram");
personList.Add(p1);
personList.Add(p2);
// Someone can not add any other object then Person into personlist
object q = new object();
personList.Add(q); // Compile Error.
// while accessing personlist, No NEED for TYPE Casting
foreach(Person obj in personlist)
{
// do something, for person
}
}
}
