Collections Classes

Generic collections allow you to store an item in your collection of a specific type.

non-generic collections allow you to store objects of any type all inheriting form the System.Object class.

The biggest difference between the two types of collections, is that if you only need to store objects of a particular type (value or reference), then generic classes are much more efficient.

The reason generic classes are more efficient is that you don't have to unbox the object inside the collection to get to the class instance you have stored there.

Also it's easier to use a generic class as a programmer if all your objects are homogeneous because there is no coersion necessary for your type.

for example:

generic:

List listOfNumbers = new List();  // generic instance

list.Add(1);  list.Add(2);

if I want to pull an element out of the list, I just need to get it directly:

int  number = list[0];

// non - generic example

ArrayList list = new ArrayList();

list.Add(1);

list.Add(2);

In a non-generic collection, To assign the first stored element  to a number, I need to unbox it  from the object type.

int number = (int)list[0];

Ok,Difference between Generic and Non-generic classes?

And from what are all the interfaces inheriting methods n properties for Generic collection classes ?

Please,Ur answer is valuable to me.

Thanks.