I am wondering if the Presenter in Model-View-Presenter is allowed to do logic/actions that are non-UI centric? Is MVP solely for UI and data or can I use it for a project where I need to write to a file (via the controller / the presenter)?
What's actually the difference between the presenter and the controller?
Controller is usually associated with MVC pattern, Presenter always with MVP. There are so many flavors. Remember, goal of MVP is to allow for testing and to decouple dependencies. How you achieve it is up to you. I for example delegate all data related operation to DataService that is injected to Presenter. If you need some file writing, you better inject that service, otherwise, good luck with testing it...
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I am trying to build set of reusable components for the ASP.Net MVC3 application.
Each component is consisted of it's own model, view and controller.
The interaction between components should be solved using mediator "like" pattern.
Since the components are higher level concept (abstraction) and not "real" objects (technically component is short-lived bunch consisted of a model, view and controller functions), it is probably tricky to implement
mediator pattern.
I need good ideas how to technically implement mediator interaction between components using ASP.Net MVC3 and AJAX?
My initial question with initial problem: MVC modular GUI components
I would keep the controllers and views as simple and possible and create a service layer where all the interactions with other components and logic sits. Also I would create a separate project for the services layer so if you want to build different types of interfaces ( phone apps etc ) you can still use the same services layer. This would also enable some automated testing to check on the logic and interaction between your components. Hope this helps.
I am using MVC3 for my application and I have a question about validation. I have a Business Logic layer that is separate from my web layer where I will have a function like CreateUser, which creates a new user for the application to use. I want this function to be accessible in two places: 1) Somewhere in a controller that makes use of it and 2) in a "Setup Data" program that inserts data into the system.
I want to make use of things like ModelState.IsValid to check for all basic validation, but this won't help me for my Setup Data mode (or any other mode that doesn't go through MVC). Is there any way I can still leverage this code, but to contain all validation in my BusinessLogic layer instead of in the controller without having the BusinessLogic layer rely on MVC?
Thanks.
It looks like this article about Service Layers has what I need. Other suggestions are still welcome. Thanks.
Note that the article on service layers still means that you need a dependency on the MVC assembly. After wrestling a bit with this myself recently, I'm now of the opinion that keeping things as separate as possible is a good design. In my model assembly, I have a services folder wherein from, say, a Create() routine, I validate and throw custom exceptions.
The service layer doesn't care who or how these exceptions are consumed. In your MVC app, map them into model state errors collections or whatever. Your design is all the more solid because your model assembly doesn't depend on some validation runner making appropriate use of MVC validation attributes, collections, etc.
I also noticed the article mentions a repository. I know it's all the rage these days but if you're already using an ORM like Entity Framework, a repository is really just a DAO. Reposity is the new Singleton.
In the MVC pattern, the controller is the least reusable, compared to the other two aspects.
Now let's say I have an app (say for Ordering Pizza), which is available both as a web app and a mobile app (say iPhone). So in that case, I think the model (or data) can be reused. The view might not be reusable.
But regarding the controller, is it possible to reuse anything? Let's say if I already have a working web app, can I reuse controller logic for the mobile app as well? Also, what is and where exactly does "business logic" reside in MVC?
The controller calls a service layer. The service layer uses the model to do business logic. Controller never contains business logic. It should only delegate work to the service layer. I consider the service layer as the part that the domain model exposes, you could say it is the "Model" in MVC.
That said, I don't think the MVC frameworks really care if the controller is reusable or not. The important part is the model, which should not change because the service layer code is reused. Besides, if we write our code correctly, the controller will be a very thin layer and reusability should not be a concern.
Can you reuse the controller logic from the web app for a mobile application? I think not, but you could use the service layer. I am sceptical if even the view can be used directly from web to mobile apps, the needs are so different.
I suggest you look at Domain driven design if you are interested in application design and learning how to organize business logic.
Is to possible to have a layout for web-based architecture based on MVC where SOA is the architectural style. Or to rephrase, can services be part of the M,V, C of MVC.If so, what kinds of services can be included in each of them. Also, can you give me a real world example?
In a SOA application you are typically not including the front end (presentation layer). You are consuming those services in your MVC application, or better yet in a separate "model" project that the MVC application uses.
Data Access -> Business Logic -> Services -> Models -> MVC
The point is to use the services to create an abstraction around the base of your application to allow for multiple clients to consume those services.
I tend to term the Model as represented in the client/presentation layer as the ViewModel, it is simply the presentation layers view of the model. Not the actual Domain model.This is needed in a SOA as the context of the consumer of the Model changes often
In SOA`s we try to get to a canonical schema for the contract, as it is quite likely that not all clients now and in the future will require the exact same view of the model.
Thus be it a web client, service client or a desktop client, if you think of the Model in MVC as the ViewModel, this allows you to abstract presentation layer things away from Service layer things, and you get closer to a canonical schema.
So an example View >> Controller >> ViewModel(Model) >> Data Contract >> Service
Examples of how to build a service stack like this can be found here:
SOA Design Pattern
The decision of whether to go with a REST architecture or a full WS-* SOAP is a separate concern and should not affect your choice of MVC as a presentation pattern.
There may of course be other constraints that preclude the use of one or the other.
Choosing a presentation pattern for a new or enterprise web development on the Microsoft platform is a daunting task, in my opinion there are only three; View Model, Model-View-Presenter (MVP) or ASP.NET MVC (a Model2 derivative).
You can read the full article here ASP.NET MVC Patterns
This depends on what you mean by SOA. If you are referring to WS-* standards, I would not recommend MVC, as you will need to write a lot of plumbing to get it to work.
If you are looking for something like a REST service, then the MVC pattern actually works quite well. The request is the HTTP location of the resource, which gets passed to the controller, which loads the data via the model, and then passes it to the view which returns it in whatever form is needed (JSON, XML, Binary, etc). Or, you can often return the result directly, depending on what framework you use.
Erick
I know that an MVC framework allows you to separate business logic, data base access and presentation, but why do we need a framework to do this.
Can't we just keep our classes separated, perhaps using different packages/folders for the model, view and controller classes?
In my opinion the thing you are talking about is the MVC pattern and not a specific framework. Of course you can go and keep all your classes within one project and still use the MVC pattern, as you have all your UI code in the views, the logic in the controllers, ...
A MVC framework on the other hand makes it easier for you to use this pattern. It may provide some base classes for controllers and a mechanism for the communication between view and controller.
I don't know if you are familiar with ASP.NET MVC. The framework itself is very small, but it helps you developing an application with the MVC pattern, as you don't have do think about the previously decribed areas...
Hope this helps
An MVC framework is a framework written to split up the the business logic, database access and presentation.
This is very useful in most web applications, and now lately into software/desktop applications.
This is due to the fact that following the MVC model, your code will be much clearer, cleaner and you keep your application DRY (Do not Repeat Yourself).
You can write your own classes and separate them into Model, View and Control. But again, you will need a framework to help you in accomplishing certain tasks. Like a List control in ASP.NET, or PHP framework being able to help you translate text between languages and so on. (Oh why reinvent the wheel?!)
MVC and framework is a different thing. MVC is just an architectural pattern, which can be applied with any project, with or without framework.
So you don't need a framework to do this. You can separate them by yourself. :)
MVC stands for “MODEL” “VIEW” “CONTROLLER”. ASP.NET MVC is an architecture to develop ASP.NET web applications in a different manner than the traditional ASP.NET web development. Web applications developed with ASP.NET MVC are even more SEO (Search Engine) friendly.
Developing ASP.NET MVC application requires Microsoft .NET Framework 3.5 or higher.
Model:
MVC model is basically a C# or VB.NET class.
A model is accessible by both controller and view.
A model can be used to
pass data from Controller to view.
A view can use model to display
data in page.
View:
View is an ASPX page without having a code behind file.
All page specific HTML generation and formatting can be done inside view.
One can use Inline code (server tags ) to develop dynamic pages.
A request to view (ASPX page) can be made only from a controller’s action method
Controller:
Controller is basically a C# or VB.NET class which inherits system.mvc.controller.
Controller is a heart of the entire MVC architecture.
Inside Controller’s class action methods can be implemented which are responsible for responding to browser OR calling views.
Controller can access and use model class to pass data to views
Controller uses ViewData to pass any data to view.
MVC is a code organization architecture style to organize your code-logic in a meaningful way for web applications. As a programmer I have almost puked when I have inherited other people's code when their code logic is all over the place and following their web application code turns into following a rabbit down the gutter hole. Why MVC? hmm.. well why should I use a filing cabinet or folders to organize my plethora of paper and not just have my papers stashed in a large pile and have others figure how they connect to each other. It increases code readability. With MVC it becomes very easy to follow code logic since you are following standard structure for a web application. Business logic is separated out from UI. Easier to delegate work decouple work on a project.
You can of course approach it yourself by segregating your classes. A framework supplies common scaffolding that you wouldn't have to build yourself. But it will also impose some structure on your code. You'll have to evaluate whether the framework helps more than it hurts.
You are correct, there are strategies that you can implement to help with separation of concerns without using MVC.
Microsoft's ASP.NET MVC framework is one strategy that can be employed, and that is what I think you are asking about.
This MVC framework makes such separation of concerns easy.
The other major advantage of MVC is testability - (depends on whether you believe in unit testing - I do).
The MVC framework ensures that all orchestration logic is on your controllers and through the FormControls collection allows full unit testing of all aspects of your application except for how it is presented.
As the MS MVC framework encourages adherence to common rules and structure of the application which should lead to greater maintainability.
The major downside of MVC is the code-in-front code weaving required for presentation, but this can be easily overcome.
Perhaps this is just a linguistic thing. I've seen "frameworks" referring to themselves as a DSL -- Domain Specific Language.
And you don't need a framework But here's something to consider: You already know for a web app you're going to want to do a few common things... route URLs, render pages, etc. Why re-write it all? For other problem domains you'll have generic things to do as well.
Hai Friends There are somemany types of architecture frame work has been there,firstly i know 2tier and 3 tier frame work ,the 3 tier and mvc ,entity framework are same but in different name's,so study a good background in any one architecture there fore if you went to any multinational companies ,you can easly score/highlight to your carrer.
Model View Controller or MVC as it is popularly called, is a software design
pattern for developing web applications. A Model View Controller pattern is made
up of the following three parts:
**Model** - The lowest level of the pattern which is responsible for maintaining data.
**View** - This is responsible for displaying all or a portion of the data to the user.
**Controller** - Software Code that controls the interactions between the Model and View