>>>Hello i want to ask
>>>1 · 3 tier applicatrions is only for web applications or it can be for desktop applications and LAN too?
>>>2. anybody knwo where can i find sample applicatiosn with ntier applications in visual basic .net
>>>
>>>Luis Martin
>>
>>1) 3 or N-tier is not tied to web programming. You can use it for desktop applications too and I think that is one of the reasons N-tier development is preferred over single tier. A common N-tier approach is 5-Tier (where it could be seen as 3-tier combining parts of it):
>>Presentation, UI, Business, Data Access, Data Storage. You may think of Presantatio+UI as a single tier (or layer). That layer is the one that changes between a web application or windows/mobile device application.
>>
>>2) There are tons of samples on the internet. You may for example check:
>>http://msdn.microsoft.com/en-us/library/ms973279.aspx
>>http://www.microsoft.com/downloads/details.aspx?FamilyID=6EB67F59-D075-4B28-B3C4-E9294FF3CF4A&displaylang=en
>>
>>Almost all applications you build using .Net and Visual Studio are N-Tier (if you do not explicitly try to make it single tier).
>>Cetin
>
>We use the 5 - layer approach (actually ours has a couple more layers) and MVP pattern for our desktop and web apps.
>
>Luis, if you are interested, there are some good podcasts with examples on the MVP pattern here:
>
>http://polymorphicpodcast.com/shows/mv-patterns/
>
>As someone pointed out in another thread, there are more design patterns to choose from including the MVC, MVP, and now the MVPC pattern :) Lots more to read up on. Lots of information on the web about it all.

Not only are there sample applications out there there are a number of good n-Tier frameworks. IdeaBlade (www.ideablade.com) has a product called DevForce that is one of the best n-Tier frameworks I have seen. It works with VB.Net and C#. They have an express version that is unlimited free use for applications with up to 10 tables. DevForce allows you to write UI neutral business objects and tie them to UIs using WinForms, ASP.Net, Silverlight, or WPF. Currently I am using it to write a desktop app and we intend to use the same business logic in a web app later.

They have very good documentation. Even if you don't use their framework you can learn a lot from the documentation.