MS's use of interfaces...

[IceAzul]

I noticed for class like ArrayList implement IList, ICollection, and IEnumerable, instead of just IList which covers them all. Are there any benefits by doing this?

[Nerseus]

You have to implement all 3 interfaces if you inherit from IList, as IList is based on the others.

 

-ner

[IceAzul]

I understand this, but MS did this:

 

class ArrayList : IList, ICollection, IEnumerable
{
   ...
}

 

instead of

class ArrayList : IList
{
   ...
}

 

You can see this from the object browser.

[Nerseus]

I did a quick test - I created a new ClassLibrary with one class that implements IList, compiled, and looked at it. It, too, shows ": IList, ICollection, IEnumerable" so that must be how .NET sees it. That kinda makes sense, as far as reflection goes - if you query a class that implements IList and IList implements ICollection, it stands to reason that querying the class through reflection will show both.

 

-nerseus