I will illustrate the usage of the following frameworks:<\/p>\n
- \n
- MvcContrib<\/a> bringing useful extension methods and strongly typed helpers to ASP.NET MVC<\/li>\n
- AutoMapper<\/a> enabling easy mapping between the domain and the view models<\/li>\n
- FluentValidation<\/a> – a small validation library for .NET that uses a fluent interface and lambda expressions for building validation rules for your business objects<\/li>\n
- NHibernate<\/a> \u2013 a popular ORM in the .NET world<\/li>\n
- FluentNHibernate<\/a> – a statically compiled alternative to NHibernate’s standard hbm xml mapping<\/li>\n
- Spring.NET<\/a> \u2013 object container and dependency Injection framework for .NET<\/li>\n
- Rhino.Mocks<\/a> – A dynamic mock object framework for the .Net platform. It’s purpose is to ease testing by allowing the developer to create mock implementations of custom objects and verify the interactions using unit testing<\/li>\n<\/ul>\n
<\/p>\n
Armed with this arsenal of frameworks let\u2019s start exploring the solution structure. I\u2019ve opted for 2 projects solution but in many real world applications more levels of abstraction could be brought to the business layer. Personally I favor to have less big assemblies rather than many small assemblies into the solution. Fewer the assemblies, faster the load time and faster the IDE. In this case particular attention should be brought to bring proper separation of concerns inside the same assembly<\/p>\n
![\"project_structure\"](\"http:\/\/dev.bratched.fr\/en\/wp-content\/uploads\/sites\/3\/2010\/05\/project_structure.png\")
<\/a><\/p>\n<\/p>\n
<\/p>\n
The domain consists of a single User class and a repository interface defining the different operations on this model:<\/p>\n
![\"Domain\"](\"http:\/\/dev.bratched.fr\/en\/wp-content\/uploads\/sites\/3\/2010\/05\/Domain.png\")
<\/a><\/p>\n<\/p>\n
Mapping<\/h1>\n
The next step is to define the mapping between our domain and a relational model expressed in a fluent manner:<\/p>\n
\npublic class UserMap : ClassMap<User>\n{\n\u00a0\u00a0\u00a0 public UserMap()\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Table(\"users\");\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Id(x => x.Id, \"usr_id\");\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Map(x => x.FirstName, \"usr_firstname\");\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Map(x => x.LastName, \"usr_lastname\");\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Map(x => x.Age, \"usr_age\");\n\u00a0\u00a0\u00a0 }\n}<\/pre>\n<\/div>\n<\/p>\n
And here\u2019s the implementation of the repository:<\/p>\n
\npublic class SqlUsersRepository : HibernateDaoSupport, IUsersRepository\n{\n\u00a0\u00a0 public IEnumerable<User> GetUsers()\n\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return HibernateTemplate.LoadAll<User>();\n\u00a0\u00a0 }\n\n\u00a0\u00a0 public User Get(int id)\n\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return HibernateTemplate.Get<User>(id);\n\u00a0\u00a0 }\n\n\u00a0\u00a0 public void Delete(int id)\n\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 HibernateTemplate.Delete(new User { Id = id });\n\u00a0\u00a0 }\n\n\u00a0\u00a0 public int Save(User user)\n\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return (int)HibernateTemplate.Save(user);\n\u00a0\u00a0 }\n\n\u00a0\u00a0 public void Update(User user)\n\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 HibernateTemplate.Update(user);\n\u00a0\u00a0 }\n}<\/pre>\n<\/div>\nHibernateDaoSupport<\/em> is a base class defined by the Spring Framework managing SQL transactions and NHibernate session.<\/p>\n
Once we have implemented the data access layer we could move on to the web part. The application consists of a single RESTful UsersController allowing the standard CRUD operations with our users model. As all our views are strongly typed we shall define a view model for each view and a mapping between the domain model and this view model. In our simple case the view model will simply have the same structure as the domain model but in real world scenarios it will be a projection of the domain model for a particular view.<\/p>\n
\n[Validator(typeof(UserViewModelValidator))]\npublic class UserViewModel\n{\n\u00a0\u00a0\u00a0\u00a0 public int Id { get; set; }\n\u00a0\u00a0\u00a0\u00a0 public string FirstName { get; set; }\n\u00a0\u00a0\u00a0\u00a0 public string LastName { get; set; }\n\u00a0\u00a0\u00a0\u00a0 public int? Age { get; set; }\n}<\/pre>\n<\/div>\nAnd the respective validator:<\/p>\n
\npublic class UserViewModelValidator : AbstractValidator<UserViewModel>\n{\n\u00a0\u00a0\u00a0 public UserViewModelValidator()\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 RuleFor(x => x.FirstName)\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .NotEmpty()\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .WithMessage(\"First name is required\")\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .DisplayName(\"First name *\");\n\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 RuleFor(x => x.LastName)\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .NotEmpty()\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .WithMessage(\"Last name is required\")\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .DisplayName(\"Last name *\");\n\u00a0\u00a0\u00a0 }\n}<\/pre>\n<\/div>\nAnd mapper between the domain and view model:<\/p>\n
\npublic class UserMapper : IMapper\n{\n\u00a0\u00a0\u00a0 static UserMapper()\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Mapper.CreateMap<User, UserViewModel>();\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Mapper.CreateMap<UserViewModel, User>();\n\u00a0\u00a0\u00a0 }\n\n\u00a0\u00a0\u00a0 public object Map(object source, Type sourceType, Type destinationType)\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return Mapper.Map(source, sourceType, destinationType);\n\u00a0\u00a0\u00a0 }\n}<\/pre>\n<\/div>\nThis bidirectional mapper will be used by our RESTful controller:<\/p>\n
\npublic class UsersController : BaseController<IUsersRepository>\n{\n\u00a0\u00a0\u00a0 public UsersController(IUsersRepository repository, IMapper userMapper) \n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 : base(repository, userMapper)\n\u00a0\u00a0\u00a0 { }\n\n\u00a0\u00a0\u00a0 [AutoMap(typeof(IEnumerable<User>), typeof(IEnumerable<UserViewModel>))]\n\u00a0\u00a0\u00a0 public ActionResult Index()\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ return all users\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 var users = Repository.GetUsers();\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return View(users);\n\n\u00a0\u00a0\u00a0 }\n\n\u00a0\u00a0\u00a0 public ActionResult New()\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ return an HTML form for describing a new user\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return View();\n\u00a0\u00a0\u00a0 }\n\n\u00a0\u00a0\u00a0 [HttpPost]\n\u00a0\u00a0\u00a0 [AutoMap(typeof(User), typeof(UserViewModel))]\n\u00a0\u00a0\u00a0 public ActionResult Create(UserViewModel userView)\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ create a new user\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 if (!ModelState.IsValid)\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return View(\"New\", userView);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 }\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 var user = (User)ModelMapper.Map(userView, typeof(UserViewModel), typeof(User));\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Repository.Save(user);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return RedirectToAction(\"Index\", \"Users\");\n\u00a0\u00a0\u00a0 }\n\n\u00a0\u00a0\u00a0 [AutoMap(typeof(User), typeof(UserViewModel))]\n\u00a0\u00a0\u00a0 public ActionResult Show(int id)\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ find and return a specific user\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 var user = Repository.Get(id);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return View(user);\n\u00a0\u00a0\u00a0 }\n\n\u00a0\u00a0\u00a0 [AutoMap(typeof(User), typeof(UserViewModel))]\n\u00a0\u00a0\u00a0 public ActionResult Edit(int id)\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ return an HTML form for editing a specific user\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 var user = Repository.Get(id);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return View(user);\n\u00a0\u00a0\u00a0 }\n\n\u00a0\u00a0\u00a0 [HttpPut]\n\u00a0\u00a0\u00a0 public ActionResult Update(UserViewModel userView)\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ find and update a specific user\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 if (!ModelState.IsValid)\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return View(\"Edit\", userView);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 }\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 var user = (User)ModelMapper.Map(userView, typeof(UserViewModel), typeof(User));\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Repository.Update(user);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return RedirectToAction(\"Index\", \"Users\");\n\u00a0\u00a0\u00a0 }\n\n\u00a0\u00a0\u00a0 [HttpDelete]\n\u00a0\u00a0\u00a0 public ActionResult Destroy(int id)\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ delete a specific user\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Repository.Delete(id);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return RedirectToAction(\"Index\", \"Users\");\n\u00a0\u00a0\u00a0 }\n}<\/pre>\n<\/div>\nNotice the AutoMapAttribute<\/em>. This is a custom attribute allowing us to automatically convert the domain model retrieved by the repository to a view model and present it to the view:<\/p>\n
\n[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]\npublic class AutoMapAttribute : ActionFilterAttribute\n{\n\u00a0\u00a0\u00a0 public Type SourceType { get; private set; }\n\u00a0\u00a0\u00a0 public Type DestType { get; private set; }\n\n\u00a0\u00a0\u00a0 public AutoMapAttribute(Type sourceType, Type destType)\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 SourceType = sourceType;\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 DestType = destType;\n\u00a0\u00a0\u00a0 }\n\n\u00a0\u00a0\u00a0 public override void OnActionExecuted(ActionExecutedContext filterContext)\n\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 base.OnActionExecuted(filterContext);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 var controller = filterContext.Controller as IModelMapperController;\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 if (controller == null)\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return;\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 }\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 var model = filterContext.Controller.ViewData.Model;\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 if (model != null && SourceType.IsAssignableFrom(model.GetType()))\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 var viewModel = controller.ModelMapper.Map(model, SourceType, DestType);\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 filterContext.Controller.ViewData.Model = viewModel;\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 }\n\u00a0\u00a0\u00a0 }\n}<\/pre>\n<\/div>\nThe OnActionExecuted<\/a> method will be called after each action method has finished executing and it will use the model passed to the view and convert it to the appropriate view model. It simply substitutes the ViewData.Model<\/em> property with the appropriate view model to finally pass it to the view for rendering.<\/p>\n
The controller follows the standard RESTful conventions for naming the action and the HTTP verbs:<\/p>\n
- AutoMapper<\/a> enabling easy mapping between the domain and the view models<\/li>\n