Article Discussion: Class Frameworks in VB .NET

Class Frameworks in VB .NET If you have any questions or comments about this article please post them here.

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Hii

a very nice article for beginners to move to object oriented world. it is always considered to be a good idea to develop BOs for etities in any application. but i have a confusion in this approach. if i chose to use BOs for entities like customers, items, invoices etc. how would i create lists of these objects. it is often required to show lists of invoices or list of customers etc. data grid and other controls provide data binding features which can be very helpful. but by using BOs, how would i bind those controls to datasets.

one solution is to expose dataview property from the class that could be used to bind it to the data grid. but it is not a good idea as we would lose the benefit of encapsulation and similar stuff.

another method is to develop a separate list objects that implement ilist and other interfaces so that we could bind these objects to these controls directly.

since you wrote this fine article, could you please explain your views in this area. any suggestions. what method is preferable or any other method to efficiently achieve this functionality.

thank you
Bilal

I havn't read the article, but it seems John, missed out the collection and engine part of the discussion.

The common approached taken in the large business application is called ECC pattern, which refers to a set of classes representing an entity. this set contains 3 classes. Entity, Collection/Array, Engine.

Now you pointed out the fact that you often need a list of entities, thats where the collection class come in. You return a collection of the entities. Or arrays if the situation doesn't require you to dynamically adjust collection sizes.

Engine might not have been mentioned in the article, so ill explaining here.

Engine is the class containing static methods that fills up the collection and entity classes. eg, it would have methods like, GetAllUsers, or GetUser(int userId) etc etc

HTH

James

i'm a biggner in vb.net

but i know little thing about it..i want to build a database class

for example :

1- first i want to connect to sqlserver.
2-after that , several properties and functions that i must have like
add, delete and others...

generic function for select ..that i give a table name,condition and coloumn as parameter..

(( if you can i want just simple code as possible becouse i'm just a biggner and thank you allllllll))

I do have one question...being relatively new to oop...on the update button click am I missing something. It says only 4 lines would be needed. Wouldn't it be necessary to instantiate a new product object to access the properties. Also is it possible to see your completed code? You reference it in the article but I don't see anywhere where it can be accessed. Any help would be greatly appreciated. Once again, very nice article and I found it very helpful in clearing up some oop issues I was having.