CollectionBase vs generics

Question

I am migrating an application from .NET 1.1 to .NET 2.0. Should I remove all uses of CollectionBase? If so, what is the best strategy for migration?

Answer 1

Yes, the best classes to look at are in System.Collections.Generic.
I usually use List.

There are two approaches you can use either:

A

public class MyClass
{
  public List<MyItem> Items;
}

B

public class MyItemCollection : List<MyItem>
{
}

public class MyClass
{
  public MyItemCollection Items;
}

The two approaches only differ very slightly and you only need to use method (B) if you plan on extending the functionality of List.

Here's a link with more info:
http://msdn.microsoft.com/en-us/library/6sh2ey19(VS.80).aspx

With regards to the classes that you've already implemented, you can remove all of the functions which are specified in the IList interface. e.g.

public int Add(InstrumentTradeDataRow instTrade) { return List.Add(instTrade); }

This can be removed because List already implements a type safe Add function for you.

See this link for more information:
http://msdn.microsoft.com/en-us/library/3wcytfd1(VS.80).aspx

Answer 2

Generally, List<T> does most of what you normally want. If you want to customize behaviour, you should inherit from Collection<T> - this has virtual methods so you can tweak behaviour when adding/removing/updating etc. You can't do this with List<T> since there are no (uesful) virtual methods.