c# When should I use List and when should I use arraylist?

As the title says when should I use List and when should I use ArrayList?

Thanks

Solution 1:

The main time to use ArrayList is in .NET 1.1

Other than that, List<T> all the way (for your local T)...

For those (rare) cases where you don't know the type up-front (and can't use generics), even List<object> is more helpful than ArrayList (IMO).

Solution 2:

You should always use List<TypeOfChoice> (introduced in .NET 2.0 with generics) since it is TypeSafe and faster than ArrayList (no un-necessary boxing/unboxing).

Only case I could think of where an ArrayList could be handy is if you need to interface with old stuff (.NET 1.1) or you need an array of objects of different type and you load up everything as object - but you could do the latter with List<Object> which is generally better.

Solution 3:

Since List is a generic class, I would tend to always use List.

ArrayList is a .NET 1.x class (still available & valid though), but it is not 'typed'/generic, so you'll need to cast items from 'object' back to the desired type; whereas when using List, you don't have to do that.