N-Tier ASP.Net Architecture [duplicate]

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A modern n-layer asp.net web application sample?

I'm having a hard time trying to design a solid N-Tier framework in ASP.Net. I know the basic fundementals: BLL, DAL, and Business Objects, etc. What I can't understand is the actual flow of the application and what the return types in the BLL and DAL should be.

Most articles I've read have suggested that the BLL and DAL communicate via Business Objects. However I don't see the real benefit if I have to instantiate the Business Object twice during each pass.

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Does anyone have any links to good tutorials/sample applications that could guide me in the right direction?

Thanks

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First, you must understand that tiers and layers are different things, although they are often confused. A layer is a software abstraction. the L in DAL stands for Layer. The last L in BLL stands for Layer.

A tier is a physical seperation of some type. At the loosest definition, merely putting you DAL in a seperate assembly is considered a Tier, although I am a bit more narrow in my definition. I consider a tier to be a physically seperated component that does not require being run on the same computer (although it may run on it, it doesn't need to).

To answer your question, though. Yes, Business Objects are typically used to transfer data (also called Data Transfer Objects, or DTO's). I'm not sure what you mean by having to instantiate the object twice. Can you be more specific?

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Don't know if you've already run into this article on msdn. If not it could be worth reading as they discuss designing tiers in general and DAL in particular, differences, pros and cons of different approaches. I think they use the same terminology as you do. Designing Data Tier Components and Passing Data Through Tiers

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