readonly wrapper for a collection

[Ashish]

hi All,
I want to create a readonly wrapper for my strongly typed collection, so
that when i expose it from my containing object as readonly, other
objects are not able to modify it

much like Arraylist.Readonly but strongly typed..

can i inherit some class in .net or would i have to create two
collection classes of the same return Type ?

comments ?, suggestions ?

regards
-ashish

 

[Cor Ligthert [MVP]]

Ashish,

Can you rephrase your question and than with less words as 'strongly typed'
, 'wrapper' etc.?

A returned property from an instanced object, which is set in the class of
that readonly, is forever read only (if it is not overloaded).

Cor

 

[Carlos J. Quintero [VB MVP]]

Create your strongly typed collection inheriting from
System.Collections.ReadOnlyCollectionBase.

--

Best regards,

Carlos J. Quintero

MZ-Tools: Productivity add-ins for Visual Studio .NET, VB6, VB5 and VBA
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[Ashish]

for example i have my Order class that class contains OrderItems
Collection (strongly typed collection of OrderItems).

Orders Class exposes a readonly property called Items, Ideally what i
would like to add/remove order items through Orders.AddItem method and
not through Items.Add method, but i still want the order class to be
able to add items in the orderitems collection.

this can be a little confusing, but please let me know and i cal explain
with some code samples.

regards
-ashish

 

[Cor Ligthert [MVP]]

Ashish,

I have the idea you mean this, I made a simple sample for you.

http://www.windowsformsdatagridhelp.com/default.aspx?ID=b94e5f61-ef37-4b01-a1e1-aabd33779b09

You can try it and tell us if it is what you mean

Cor

 

[Ashish]

Hi Cor,

thanks for the effort, i saw the code and what i want to do is add items
through order object. in other words do this

myOrder.AddItem(123)

instead of

myOrder.OrderItems.add(123)

and ideally i would like to throw exception when a user tries to do
'myOrder.OrderItems.add(123)', is there any way to expose this
collection as a true readonly ? or would i have to create and maintain 2
collections

regards
-ashish

 

[Cor Ligthert [MVP]]

Ashish,

And how do you want to get those orderitems?

Cor

 

[Ashish]

well the order class would maintain and expose those orderitems through
the readonly items property

like

Dim myOrder as new Order(1002)

dim myItems as OrderItemCollection = myOrder.Items


but when i call

myOrder.Items.Add(new object)

it should throw error, saying that this collection is readonly