Question List(of T) with items accessible by name and index

[jeanjeanot]

Hi all,
I want to build my own class. In it, I need to recreate a behavior we can see in DataTable and in some other places : accessing items by their name or by their index. How can I reproduce such a behavior. Here's what I mean :

'Here's one way to access the data
A = MyObj(0).value
'Here's the other way I would like to acces it
A = MyObj("Blablabla").value

How can I create my class so I can access items in an array (or list preferably) by it's index or an unique Name ?
Thank you !

Jean

 

[JohnH]

Inherit Collection(Of T) when making a new collection if you want to override existing members, or to allow others to do that if they inherit your class.
You need to add a property that takes a String parameter.
To access a property without actually writing it in code you have to declare the property Default. Since there is already a default property named Item, you use that name too and declare your property Overloads.

 

[jmcilhinney]

Inherit the System.Collections.ObjectModel.KeyedCollection(Of TKey, TItem) class.

 

[jmcilhinney]

Note that inheriting Collection(Of T) will give you a class that behaves much like List(Of T), which will not give you the dictionary-like behaviour, i.e. retrieval by key, that you want. The KeyedCollection(Of TKey, TItem) class has both retrieval by index and retrieval by key.

 

[jeanjeanot]

Thanks guy for the fast replies. It is exactly what I was looking for. I didn't know that a property could have arguments!!! I've learned to code by myself and I'm always suprised to see how far I went in some area of coding and still not knowing the basic things in others...