What design pattern should I adhere to in order to develop an asp.net application?
The best practice I've seen today is to decouple all business logic from the presentation tier. Classic ASP.NET Webforms tend to make this a little more difficult and encourage lazy programming because you can use all events outside of the page rather than enforcing good code separation and single responsibility.
If you want to use the ASP.NET MVC framework, you will most likely have a framework that facilitates better coding practice. However, you can still find ways to revert to webforms coding style.
If you focus on the Single Responsibility Principle and ASP.NET MVC , you're about to get off to a great start. Domain Driven Design is also worth a look.
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This may depend on the goals and objectives of the applications. Will it be user-centric? Pretty / Ajaxy? SOAP service?
Design templates can help make life easier. If you are wrong, then it can make life more difficult. Architectural patterns, behavioral patterns, structural patterns, and data semantics can only be resolved in the context of an application of functionality that is ultimately inferior.
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Model-view-controller (MVC) is the popular one used for developing this kind of thing
There's a really good, free architecture guide available on patterns and methods. It goes into detail on many of the different patterns and where they can be used when developing an ASP.NET application (and many other types).
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