With WebForms, if I wanted to run a method on every page load, then I would call this method in the Page_Load() method of the main Master Page.
Is there an alternative, perhaps better solution, when using MVC3?
you could create a class base controller
public class BaseController : Controller
{
public BaseController()
{
// your code here
}
}
and let every new controller of yours impelement the base controller like
public class MyController: BaseController
also i have found the basecontroller very usefull to store other functions i need a lot in other controllers
I think the most appropriate way to do this in MVC is with filters
MSDN provides a good description of them, and there are dozens of articles and explanatins about them on the net, such as this one
EDIT
This sample is even better: It provides a simple action filter, which is then registered in global.asax, and executed on every request, before the actual Action in the relevan controller executes. Such concept allows you to access the request object, and modify whatever you want before the actual controller is executing.
You could put the code in the constructor of the controller.
Like this:
public class FooController : Controller
{
public FooController()
{
doThings();
}
Related
Say I have a controller FooController which has a bunch of action methods. Some of these methods would I like to override, but none of the methods are marked as virtual and I do not want to change the code of FooController.
So I implement a CustomFooController (not inheriting from FooController) and write new versions of the methods that I want.
Now I want to route first to CustomFooController and if the action is not available there I want to default to FooController. I have set up this route config to override the route:
routes.MapRoute(
"customFoo",
"foo/{action}",
new { controller = "CustomFoo", action = UrlParameter.Optional }
);
Here is some example definitions:
public class FooController : Controller
{
public ActionResult Bar { ... }
public ActionResult Baz { ... }
}
public class CustomFooController : Controller
{
public ActionResult Bar { ... }
}
So when accessing /Foo/Bar we should hit CustomFooController.Bar() and when accessing /Foo/Baz we should hit FooController.Baz() since Baz() is not implemented in CustomFooController.
But I get "The resource cannot be found", I understand why, but can I somehow work around it without modifying FooController?
You might want to have a look at HandleUnknownAction() (see msdn reference page).
It is invoked when a request matches a controller, but no method with the specified action name is found in that controller.
So you could override that method in your CustomFooController to redirect to the appropriate action in FooController (or even other controllers based on your custom inspection of request related data).
Redirection can be done with RedirectToAction() (see msdn reference page)
I think I found a neat solution myself. Since I don't want to modify FooController and a bunch of other controllers from another application I'm extending (and relying on updates from) I decided to use extension method MapMvcAttributeRoutes() from System.Web.Mvc.RouteCollectionAttributeRoutingExtensions in my startup RouteConfig in order to first match with route attributes on e.g. my CustomFooController which takes precedence over the conventional routing.
Just to be on the safe side: HandleUnknownAction() is implemented only in CustomFooController. You don't have to modify FooController (or other controllers).
Background: symfony3
I have just stuck in the fact that redirectToRoute and addFlash methods in controller are protected in symfony. I have a separate class for action.
namespace AppBundle\Action;
class Base {
public function __construct($controller) {
$this->controller = $controller;
}
}
As you can see base action class requires a controller. Basically it is logical because action class is part of a controller and should have access to all its methods. However I cannot call $this->controller->addFlash as it is protected. If it is protected then there might be some reason for it. I cannot find it. Can you please hint me how I can change my action class so that it could use controller methods.
The variant about extending action from a controller does not fit me as I have additional functionality in the main controller. It is configured in a proper way.
Update: my goal is to devide controller functionality by responsibility. I invented an action class. My end code look like following:
public function editAction() {
$instance = new \AppBundle\Action\MyController\Edit($this);
return $insance->run();
}
In this case I keep controller clean and not verbose.
Here is a link to Symfony Controller Trait, that you can duplicate, if you really want to work that way.
But since you are injecting a whole symfony controller into your own controllers, you will be better off with extending instead. Injection is used here for injecting separate service by their IDs.
I have a UserController that has a Destroy function. It is a rather complex function because it demands to destroy all user's data. I have another action, from the Admin panel that deletes all data from a specific set of users.
Since I don't want to replicate the code from the UserController, I would like to call the Destroy function from UserController for each User to destroy its data.
How should I proceed?
Thanks in advance.
Why not move this functionality to a common class method which can be accessed from both the controllers as needed ?
public class UserManager
{
public void Destroy(List<int> userIdsToDestroy)
{
foreach(var userId in userIdsToDestroy)
{
//Execute code to destroy
}
}
}
and from your action methods, you can call it like
var mgr = new UserManager();
var badUsers = new List<int> { 1,2,3};
mgr.Destroy(badUsers);
Update the badUsers variable value as needed based on from where you are calling it.
Shared functionality like this would ideally be in a business layer, and both controllers would call that code. If it's a little app, you could just create a separate folder structure for shared code. Larger projects would have a business layer dll.
Why not make the Destroy() method as a Non-Action method then like
[Non-Action]
public void Destroy(User user)
{
// code goes here
}
You can as well make this Destroy() function as part of your business layer logic instead of handling this in controller. In that case, you call it from anywhere.
If you want it to be #controller, you can as well consider usig [ChildActionOnly] action filter attribute.
I am learning asp.net mvc3. one example I found online is to show me how to use IOC.
public class HomeController : Controller
{
private IHelloService _service;
public HomeController():this(new HelloService())
{}
public HomeController(IHelloService service)
{
_service = service;
}
}
there are two constructors in this example. I understand the second one. the first one I understand what that for, but to me, it seems like extra code, you will never need it.
can someone please explain to me whats the point to add the first constructor.
public HomeController():this(new HelloService())
{}
When the MVC Framework instantiates a controller, it uses the default (parameter-less) constructor.
By default, you are injecting a concrete IHelloService implementation. This will be used when a user navigates to the action.
Unit Tests would use the overload and pass in the mock IHelloService implementation rather than calling the default constructor.
It can be useful if you don't use a dependency injection framework that injects this for you. In this way you never have to manually inject the object, the object will handle that by itself.
The second constructor is, of course, useful to inject custom objects when unit testing.
Normally one would need to do this:
IFoo foo = new Foo();
IBar bar = new Bar(foo);
When your constructor creates a default object you can just do this:
IBar bar = new Bar();
Bar will then create a Foo and inject it into itself.
I'm using a masterpage in my ASP.NET MVC project. This masterpage expects some ViewData to be present, which displays this on every page.
If I don't set this ViewData key in my controllers, I get an error that it can't find it. However, I don't want to set the ViewData in every controller (I don't want to say ViewData["foo"] = GetFoo(); in every controller).
So, I was thinking of setting this in a base controller, and have every controller inherit from this base controller. In the base controller default constructur, I set the ViewData. I found a similar approach here: http://www.asp.net/learn/MVC/tutorial-13-cs.aspx. So far so good, this works... but the problem is that this data comes from a database somewhere.
Now when I want to Unit Test my controllers, the ones that inherit from the base controller call its default constructor. In the default constructor, I initialize my repository class to get this data from the database. Result: my unit tests fail, since it can't access the data (and I certainly don't want them to access this data).
I also don't want to pass the correct Repository (or DataContext, whatever you name it) class to every controller which in turn pass it to the default controller, which I could then mock with my unit tests. The controllers in turn rely on other repository classes, and I would end up passing multiple parameters to the constructor. Too much work for my feeling, or am I wrong? Is there another solution?
I've tried using StructureMap but in the end I didn't feel like that is going to fix my problem, since every controller will still have to call the base constructor which will initialize the repository class, so I can't mock it.
This is a similar question but I find no satisfactory answer was given. Can I solve this in a neat way, maybe using StructureMap as a solution? Or should I jsut suck it and pass a Repository to every controller and pass it again to the base controller? Again, It feels like so much work for something so simple. Thanks!
I see two options:
First:
Set the ViewData for MasterPage in YourBaseController.OnActionExecuting() or YourBaseController.OnActionExecuted():
public class YourBaseController : Controller
{
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
// Optional: Work only for GET request
if (filterContext.RequestContext.HttpContext.Request.RequestType != "GET")
return;
// Optional: Do not work with AjaxRequests
if (filterContext.RequestContext.HttpContext.Request.IsAjaxRequest())
return;
...
filterContext.Controller.ViewData["foo"] = ...
}
}
Second:
Or create custom filter:
public class DataForMasterPageAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
// Optional: Work only for GET request
if (filterContext.RequestContext.HttpContext.Request.RequestType != "GET")
return;
// Optional: Do not work with AjaxRequests
if (filterContext.RequestContext.HttpContext.Request.IsAjaxRequest())
return;
...
filterContext.Controller.ViewData["foo"] = ...
}
}
and then apply to your controllers:
[DataForMasterPage]
public class YourController : YourBaseController
{
...
}
I think the second solution is exactly for your case.