We are building an ASP MVC3 application, where we are building the service layer and Entity model. A third party is building Views/Controllers.
Now the tricky bit is the Model. Where should it go?
My opinion is the MVC web application will just have View and controller. Our service library will have business logic and EF. But I think we should not expose EF entities directly to the web application. (or should we? ) Instead we should look at the views and create view model classes for each views. This might require creating multiple view model classes for each view.
Can anyone provide their opinion on if this is right design? If so, where should view models reside? should we create another library just for view models?
I would suggest making your models as POCO objects with CRUD functionality- you shouldn't expose the EF entities. This way your service library can be reused in other applications or interfaces if needed.
If the POCO objects you provide won't work directly as view models, then it's up to the team writing the controller to create a view model from your service objects (POCOs). That would probably (hopefully) be a very simple view model, using your POCOs as properties (maybe a view model is a list of one of your POCOs, or a combination of a couple different POCOs).
That's just my two cents...
does anyone have good links or tips on best practices concerning migrating from ASP.NET Webforms to ASP.NET MVC?
We have a large webforms application that we would like to piece by piece migrate to MVC. Here is our current setup.
Two big Webforms project (VB)
Multiple class libraries and services (C# and VB.Net)
Subsonic 2.2 Data access layer
SQL Server 2008 DB
We are considering the following:
Keep the classic webforms project running as is for now while developing.
Create new MVC project based on MVC 3 with Razor view engine
Use Nhibernate (Repository pattern) DAL
Convert/build the existing functionality module by module in the MVC project
Replace some functionality in the old webforms project with new MVC modules if possible. Integrate via eg. Iframes.
In time the new MVC app will replace the old webforms project entirely.
We would like to keep the DB as is so we also need a tool to create the Model based on the DB.
Is this a possible solution?
WebForms applications use server-side session a lot because most of the server controls use it internally. You will not be able to use any of the server controls that you used in WebForms in MVC3 (atleast without some tinkering).
MVC3 promotes the use of restful architecture, where any state is maintained in html or url or cookies, and these are reasons why I think you should revisit the decision to convert to MVC3. Do so only if it will give you a huge advantage, because I suspect you will be reinventing ground up your existing app - I suspect there will be an equal amount of effort migrating it as to while developing it new.
Again there is nothing preventing you from creating an "area" or a "region" of MVC in your webforms app, if your goal is to use MVC for future development.
If you still want to move to MVC3, take a look here
It is ok solution. Also for NHibernate you can use MyGeneration with NH plugin to generate models on top of existing DB. And it is also possible to host WebForms and MVC together in one web app. Just finished quite the same task. But used EF for DAL.
I've been using ASP.net MVC for about two years now and I'm still learning the best way to structure an application.
I wanted to throw out these ideas that I've gathered and see if they are "acceptable" ways in the community to design MVC applications.
Here is my basic layout:
DataAccess Project - Contains all repository classes, LINQ-to-SQL data contexts, Filters, and custom business objects for non-MS SQL db repositories (that LINQ-to-SQL doesn't create). The repositories typically only have basic CRUD for the object they're managing.
Service Project - Contains service classes that perform business logic. They take orders from the Controllers and tell the repositories what to do.
UI Project - Contains view models and some wrappers around things like the ConfigurationManager (for unit testing).
Main MVC Project - Contains controllers and views, along with javascript and css.
Does this seem like a good way to structure ASP.NET MVC 2 applications? Any other ideas or suggestions?
Are view models used for all output to views and input from views?
I'm leaning down the path of making view models for each business object that needs to display data in the view and making them basic classes with a bunch of properties that are all strings. This makes dealing with the views pretty easy. The service layer then needs to manage mapping properties from the view model to the business object. This is a source of some of my confusion because most of the examples I've seen on MVC/MVC2 do not use a view model unless you need something like a combo box.
If you use MVC 2's new model validation, would you then validate the viewmodel object and not have to worry about putting the validation attributes on the business objects?
How do you unit test this type of validation or should I not unit test that validation messages are returned?
Thanks!
Interesting.
One thing I do differently is that I split off my DataAccess project from my Domain project. The domain project still contains all the interfaces for my repositories but my DataAccess project contains all the concrete implementations of them.
You don't want stuff like DataContext leaking into your domain project. Following the onion architecture your domain shouldn't have any dependencies on external infrastructure... I would consider DataAccess to have that because it's directly tied to a database.
Splitting them off means that my domain doesn't have a dependency on any ORM or database, so I can swap them out easily if need be.
Cheers,
Charles
Ps. What does your project dependency look like? I've been wondering where to put my ViewModels. Maybe a separate UI project is a good idea, but I'm not entirely sure how that would work. How do they flow through the different project tiers of your application?
I am developing an ASP.NET MVC app and I've been looking into using Data Annotations on my POCO's which are defined in my Service Layer. As long as I have a reference to System.ComponentModel & System.ComponentModel.DataAnnotations this is no problem and what I like about this is that it allows me to reuse my Service Layer in a Win Forms app.
I'm now looking to do some Remote Validation using Data Annotations and have taken a look at this article: http://msdn.microsoft.com/en-us/library/ff398048(VS.100).aspx
However, to use the Data Annotations in this context I need to reference System.Web.MVC,
System.Web and System.Web.Routing. This introduces a dependency on the Web DLL's, which
limits me somewhat.
Can anyone recommend a good clean way to implement Remote Data Validation using Data Annotations that isn't coupled with ASP.NET MVC or maybe suggest a better alternative.
Thanks for the help !
I resolved this in the end by backing away from putting DataAnnotations on my POCO's and instead I put them on my ViewModels and use AutoMapper to Map between my ViewModel and POCO (which saves me some time doing tedious mapping). There's a great video on Automapper here http://perseus.franklins.net/dnrtvplayer/player.aspx?ShowNum=0155
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