Should we use Generic Collection to improve safety and performance?

Question

Should we use Generic Collection to improve safety and performance?

Answer 1

Absolutely.

A conventional collection, such as the ArrayList, implicitly stores objects.

This means, that doing this:

ArrayList list = new ArrayList();
list.Add(5);
list.Add("FooBar");

Is legitimate code. This introduces a handful of issues.

• Normally, you don't want to store different types in the same collection, and having compile time checking for this is nice.
• When you store a value type (such as the integer 5 above), it must be boxed into a reference type before it can be stored in the collection.
• When reading a value, you must cast it back from Object to the desired type.

However, you eliminate all of these issues by using a generic collection:

List list = new List();
list.Add(5);
// Compile Time Error.
list.Add("FooBar")

You also gain intellisense support when working directly with indices of the collection, instead of just generic "object" intellisense.