Custom Collections

[James T.]

Hello!

I defined a custom collection class that inherits from CollectionBase, it
works fine...

Now, I would like to add each item an ID property, so I could access items
in the collection by ID. What I need is a sample how I can generate unique
ID each time when a new Item is added to the collection?

Thanks!

James

[Oenone]

Re: Custom Collections

James T. wrote:[color=blue]
> Now, I would like to add each item an ID property, so I could access
> items in the collection by ID. What I need is a sample how I can
> generate unique ID each time when a new Item is added to the
> collection?[/color]

The way I approached this is to use actual values from within the collected
objects to provide IDs.

If I'm collecting users, I'll use the username as the identifier. This has
to be unique as each user has a unique username.

I then get my Item property to scan through the collection looking for the
user with the supplied username. If it finds it then the user is returned,
if no user is located then Nothing is returned. This also gives me a really
easy 'Exists' type function, because if Item returns Nothing then the item
doesn't exist within the collection.

It also has the advantage of dynamically updating the item keys if the
properties of the objects change. If I modify an object's Username property,
the Item key will automatically be updated with it (as they are both the
same value).

This may or may not be practical depending on what type of object you are
collecting, but worth thinking about.

--

(O)enone

[Cor Ligthert]

Re: Custom Collections

James,

Are you sure that you cannot use a GUID

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemguidclasstopic.asp

I hope this helps,

Cor

[James T.]

Re: Custom Collections

Thank you for good suggestion...

James
[color=blue][color=green]
>> Now, I would like to add each item an ID property, so I could access
>> items in the collection by ID. What I need is a sample how I can
>> generate unique ID each time when a new Item is added to the
>> collection?[/color]
>
> The way I approached this is to use actual values from within the
> collected objects to provide IDs.
>
> If I'm collecting users, I'll use the username as the identifier. This has
> to be unique as each user has a unique username.
>
> I then get my Item property to scan through the collection looking for the
> user with the supplied username. If it finds it then the user is returned,
> if no user is located then Nothing is returned. This also gives me a
> really easy 'Exists' type function, because if Item returns Nothing then
> the item doesn't exist within the collection.
>
> It also has the advantage of dynamically updating the item keys if the
> properties of the objects change. If I modify an object's Username
> property, the Item key will automatically be updated with it (as they are
> both the same value).
>
> This may or may not be practical depending on what type of object you are
> collecting, but worth thinking about.
>
> --
>
> (O)enone
>[/color]