Can I move common code from a method into a base controller with MVC4? - asp.net-mvc

Question

I have the following method in five controllers:
public ActionResult Index(string page, string title) {
var vm = new BaseViewModel();
vm.Role = GetRoleNumber(User);
vm.MenuItems = contentService.GetMenuItems("00", vm.Role);
vm.Menu = pageService.GetMenu(vm.MenuItems, Request.FilePath);
// difference code here for each controller
}
All my controllers inherit from a controller called BaseController.
Is there a way I could move this code into my base controller and call it? If so then what would be the best way to implement this?

Answer 1

This is an exact candidate for the Repository Pattern.
You could create all of these in your Repository class and call that method in each ActionResult method
public void Repository : IRepository
{
public GetMyBaseViewModel()
{
//..implementation here
}
}
public interface IRepository
{
BaseViewModel GetMyBaseViewModel();
}
....
and in your controllers :
...
public class HomeController : Controller
{
//private repository member
private readonly IRepository _repository;
//controller constructors
//injecting the repository here
public HomeController() : this(new Repository())
{
}
public HomeController(IRepository repository)
{
_repository = repository;
}
//methods that call the repository for the vm data context
public ActionResult Index()
{
var vm = _repository.GetMyBaseViewModel();
return View();
}
}

Answer 2

You could make an abstract ActionResult method in your base controller:
protected BaseViewModel vm;
public ActionResult Index(string page, string title) {
vm = new BaseViewModel();
vm.Role = GetRoleNumber(User);
vm.MenuItems = contentService.GetMenuItems("00", vm.Role);
vm.Menu = pageService.GetMenu(vm.MenuItems, Request.FilePath);
try
{
return IndexSupplemental();
}
catch(NotImplementedException ex)
{
// Log and move on; the abstract method is not implemented.
}
return View();
}
protected abstract ActionResult IndexSupplemental();
Then every controller would have to implement this abstract method.

Answer 3

You can move it to a method in your base controller and call it when you need it.
public class BaseController : Controller
{
protected BaseViewModel _viewModel;
public void InitializeViewModel() {
vm = new BaseViewModel();
vm.Role = GetRoleNumber(User);
vm.MenuItems = contentService.GetMenuItems("00", vm.Role);
vm.Menu = pageService.GetMenu(vm.MenuItems, Request.FilePath);
}
}
An example:
public class MyController : BaseController
{
public ActionResult Index(string page, string title)
{
InitializeViewModel();
DoSomething(_viewModel);
}
}

Answer 4

In my projects most of my actions will return a viewmodel that inherits from the BaseViewModel but there are exceptions to this. So what I did was something like this in ControllerBase:
protected override void OnActionExecuted(ActionExecutedContext filterContext)
{
base.OnActionExecuted(filterContext);
var authData = GetUserData();
if (authData != null)
{
var result = filterContext.Result as ViewResult;
if (result != null)
{
var vm = result.Model as ViewModelBase;
if (vm != null)
{
vm.UserId = authData.UserID;
vm.UserName = User.Identity.Name;
}
}
}
}
What you could do otherwise, as I expect your ViewModel to be of different types, is to create a method similar to this in ControllerBase:
NOTE This does not do what you want. I'm just showing a technique for creating a new instance of a derived class with some initialization code.
protected T Command<T>() where T : BaseCommand, new()
{
var command = new T();
command.IP = Request.UserHostAddress;
if (User != null && User.Identity.IsAuthenticated)
{
var authData = GetUserData();
if (authData != null)
{
command.UserId = authData.UserID;
}
}
return command;
}
Which would be used as
var command = Command<CreateUserCommand>();