Unique fields in a Custom Collection

[gpoch]

I've been studing over my code and I am looking for some constructive criticism?

Suppose you have a collection of objects. Each object must contain a unique integer field called site (the site range can be from 0 to 500). So if I add or remove objects from the collection. I need to be able to display a listbox of current sites available.

So this is what I did... Inherited from a List class and created a function that would enumerate through itself and return an arraylist of sites available.

BTW, I'm storing the collection in XML, but Ill probably change it to SQL Express.

I'm pretty new to programming so Im really trying to focas on best programming practices.

Thanks again.

[SIZE=2][COLOR=#0000ff]Public [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE][SIZE=2] GetAvailableSites() [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] ArrayList[/SIZE]
 
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] al [/SIZE][SIZE=2][COLOR=#0000ff]As [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]New[/COLOR][/SIZE][SIZE=2] ArrayList[/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] cam [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2] Camera[/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] i [/SIZE][SIZE=2][COLOR=#0000ff]As [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Integer[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Dim[/COLOR][/SIZE][SIZE=2] exists [/SIZE][SIZE=2][COLOR=#0000ff]As[/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Boolean[/COLOR][/SIZE][SIZE=2] = [/SIZE][SIZE=2][COLOR=#0000ff]False[/COLOR][/SIZE]
 
[SIZE=2][COLOR=#008000]'find addresses that are available for new entries[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]For[/COLOR][/SIZE][SIZE=2] i = MIN_SITE [/SIZE][SIZE=2][COLOR=#0000ff]To[/COLOR][/SIZE][SIZE=2] MAX_SITE[/SIZE]
[SIZE=2][COLOR=#0000ff]For [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Each[/COLOR][/SIZE][SIZE=2] cam [/SIZE][SIZE=2][COLOR=#0000ff]In [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Me[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE][SIZE=2] cam.Site = i [/SIZE][SIZE=2][COLOR=#0000ff]Then[/COLOR][/SIZE]
[SIZE=2]exists = [/SIZE][SIZE=2][COLOR=#0000ff]True[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Exit [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]For[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]End [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]If[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Next[/COLOR][/SIZE]
 
[SIZE=2][COLOR=#0000ff]If [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Not[/COLOR][/SIZE][SIZE=2] exists [/SIZE][SIZE=2][COLOR=#0000ff]Then[/COLOR][/SIZE][SIZE=2] al.Add(i)[/SIZE]
[SIZE=2]exists = [/SIZE][SIZE=2][COLOR=#0000ff]False[/COLOR][/SIZE]
[SIZE=2][COLOR=#0000ff]Next[/COLOR][/SIZE]
 
[SIZE=2][COLOR=#0000ff]Return[/COLOR][/SIZE][SIZE=2] al[/SIZE]
 
[SIZE=2][COLOR=#0000ff]End [/COLOR][/SIZE][SIZE=2][COLOR=#0000ff]Function[/COLOR][/SIZE]