I know how to get the current controller name
HttpContext.Current.Request.RequestContext.RouteData.Values["controller"].ToString();
But is there any way to get the current controller instance in some class (not in an action and not in a view)?
By default you can only access the current Controller inside a controller with ControllerContext.Controller or inside a view with ViewContext.Context. To access it from some class you need to implement a custom ControllerFactory which stores the controller instance somewhere and retrieve it from there. E.g in the Request.Items:
public class MyControllerFactory : DefaultControllerFactory
{
public override IController CreateController(RequestContext requestContext, string controllerName)
{
var controller = base.CreateController(requestContext, controllerName);
HttpContext.Current.Items["controllerInstance"] = controller;
return controller;
}
}
Then you register it in your Application_Start:
ControllerBuilder.Current.SetControllerFactory(new MyControllerFactory());
And you can get the controller instance later:
public class SomeClass
{
public SomeClass()
{
var controller = (IController)HttpContext.Current.Items["controllerInstance"];
}
}
But I would find some another way to pass the controller instance to my class instead of this "hacky" workaround.
Someone will have to correct me if what I am doing is detrimental to the whole Asp.Net page life cycle / whatever but surely you can do this:
In controller
ViewBag.CurrentController = this;
In view
var c = ViewBag.CurrentController;
var m1 = BaseController.RenderViewToString(c, "~/Views/Test/_Partial.cshtml", null);
In my case, I had a base controller that all controllers extend. In that base controller lived a static method called RenderViewToString and it required a controller. Since I figured I could just instantiate a new instance of an empty controller at this point for c, I just sent it to the view in the lovely ViewBag container that exists in the world of Asp.Net MVC. For reasons I could not go into now, I could not retrieve the string in the controller and send just that back to the view (this was what I had done earlier before requirements changed).
The reason I have done it this way is in other languages like PHP and JS, there are similar simple ways to transfer classes around.
Related
im using laravel 5.
I need to call a controller function but this should be done in another controller.
I dont know how to do this
public function examplefunction(){
//stuff
}
And i have a Route for this function, so at
public function otherfunctioninothercontroller(){
// I need examplefunction here
}
how Can i do this?
1) First way
use App\Http\Controllers\OtherController;
class TestController extends Controller
{
public function index()
{
//Calling a method that is from the OtherController
$result = (new OtherController)->method();
}
}
2) Second way
app('App\Http\Controllers\OtherController')->method();
Both way you can get another controller function.
If they are not in the same folder, place use namespace\to\ExampleClass; on top of your file, then you are able to instantiate your controller.
You can simply instantiate the controller and call the desired method as follows
FirstController.php:
namespace App\Http\Controllers;
class FirstController extends Controller {
public function examplefunction() {
// TODO: implement functionality
}
}
SecondController.php:
namespace App\Http\Controllers;
class SecondController extends Controller {
public function test() {
$object = new FirstController();
$object->examplefunction();
}
}
Now, after i've answered the question, i would like to add the following comment:
Controllers are classes, all rules that applies to normal classes can be applied to them
However, instantiating a controller directly inside another controller to call a desired method signifies a problem in your design for the following 2 reasons:
A controller cannot obtain an instance of another controller directly
Controller should contain as little business logic as possible, and if possible none
The closest possible solution to what you want (WITHOUT BREAKING MVC) is to make an HTTP request to the route that points to the desired method (using cURL, for example) and read the response as the returned data
But this still doesn't make much sense in this scenario because after all you're making an HTTP request from a method in a controller in your project on your server to a method in a controller in your project on your server, seems like unnecessary overhead, right ?
As i said earlier, a controller should contain as little business logic as possible because the logic should stay inside specialized classes (commonly known as Service Classes), and when a processing is requested the controller simply delegates the job of processing to the appropriate service class which does the processing and returns the results to the controller which in turn sends it back as a response
Now imagine if you've the following scenario:
We've got an application that consists of 3 functionalities:
A user can register an account from web application
There's a mobile application that talks to an API to register a user
There's an admin panel, which he can use to add new user
Obviously you need to create 3 controllers, but those controllers contains repeated logic, would you copy/paste the code everywhere ?
Why not encapsulate this logic inside a service class and call it from the controller when needed ?
Let's say I have Controller1 and Controller2. I want to call a function of Controller1 from inside a function placed in Controller2.
// Controller1.php
class Controller1 {
public static function f1()
{
}
}
And on the other controller:
// Controller2.php
use App\Http\Controllers\Controller1;
class Controller2 {
public function f2()
{
return Controller1::f1();
}
}
Points to be noted:
f1() is declared static
A call to a controller from inside another controller is a bad idea. There is no sense of meaning of controllers then. You should just redirect to web.php to save safe whole architecture like this:
class MyController {
public function aSwitchCaseFunction(Request $requestPrm){
...
//getting path string from request here
...
switch($myCase){
case CASE_1:
return redirect()->route('/a/route/path');
....
}
}
}
I'm using ViewBag.Message with the same message several times into the methods on the controller.
It is possible to declare ViewBag.Message on the top of the class, so can be used in the whole controller without repeat the code?
Assuming Razor syntax you can achieve this with.
#{string pageMessage = ViewBag.Message.ToString();}
then pageMessage is a local variable available to the page, for example:
<h1>#pageMessage</h1>
EDIT
ViewBag is a dynamic object which is a member of the Controller base class so to just specify this once in the whole controller you could put something in your controller constructor.
public class MyController : Controller
{
public MyController()
{
ViewBag.ViewTime = DateTime.Now.ToString();
}
// rest of controller code
}
I have some parameters in URL, which I would like to be present in the URL for all pages in my MVC3 app. For example:
mycompany.com/home?param=1
mycompany.com/cart?param=1
mycompany.com/logout?param=1
Whether the user is navigating to a new page or submitting a form, how can I have my parameter
be present in all my pages? Right now the only way I can think off is somehow reconstruct the URL for every new view I need to render. Is there built in functionality in MVC to do this?
Thanks
That sounds like something you should store in Session instead of updating all of your links to add the same parameter.
You could use a Session variable as the other poster suggested, or you could use a base view model which holds this static param value.
So your base view would be something like this:
public class BaseViewModel
{
public static int ParamValue = 1;
}
then in each view model you use for each view, you'd have something like this:
public class PageViewModel : BaseViewModel
{
// properties
}
This way, in each view, you can just reference #Model.ParamValue whenever you need to access it:
#Model Namespace.PageViewModel
My param value is <b>#Model.ParamValue</b>
I'm trying to implement a common controller in MVC3 to return various JSON feeds, example -
public class AjaxController : Controller
{
public ActionResult Feed1()
{
ViewBag.Json = LogicFacade.GetFeed1Json();
return View();
}
public ActionResult Feed2()
{
ViewBag.Json = LogicFacade.GetFeed2Json();
return View();
}
}
This class has 30+ methods in it, the problem is this requires implementing an IDENTICAL View for each of the Controller's methods (sigh) that writes out ViewBag.Json.
I'm assuming this is a routing issue but I'm struggling with that. The following didn't work -
Tried setting ViewBag.Json then using RedirectToAction() but that seems to reset ViewBag.Json.
Note JsonResult is not appropriate for my needs, I'm using a different JSON serialiser.
So the objective here is to maintain one View file but keep this class with seperate methods that are called by routing, and not a crappy switch statement implementation.
Any help appreciated.
Use the same view and just specify the name. You can store in the controller's view folder, if only used by one controller, or in the Shared view folder if used by more than one.
return View("SharedJsonView");
Another, perhaps better, solution would be to create your own result -- maybe deriving from JsonResult, maybe directly from ActionResult -- that creates the JSON response that you need. Look at the source code for JsonResult on http://www.codeplex.com/aspnet for ideas on how to do it.
We have an a PHP application that we are converting to MVC. The goal is to have the application remain identical in terms of URLs and HTML (SEO and the like + PHP site is still being worked on). We have a booking process made of 3 views and in the current PHP site, all these view post back to the same URL, sending a hidden field to differentiate which page/step in the booking process is being sent back (data between pages is stored in state as the query is built up).
To replicate this in MVC, we could have a single action method that all 3 pages post to, with a single binder that only populates a portion of the model depending on which page it was posted from, and the controller looks at the model and decides what stage is next in the booking process. Or if this is possible (and this is my question), set up a route that can read the POST parameters and based on the values of the POST parameters, route to a differen action method.
As far as i understand there is no support for this in MVC routing as it stands (but i would love to be wrong on this), so where would i need to look at extending MVC in order to support this? (i think multiple action methods is cleaner somehow).
Your help would be much appreciated.
I have come upon two solutions, one devised by someone I work with and then another more elegant solution by me!
The first solution was to specify a class that extends MVcRouteHandler for the specified route. This route handler could examine the route in Form of the HttpContext, read the Form data and then update the RouteData in the RequestContext.
MapRoute(routes,
"Book",
"{locale}/book",
new { controller = "Reservation", action = "Index" }).RouteHandler = new ReservationRouteHandler();
The ReservationRouteHandler looks like this:
public class ReservationRouteHandler: MvcRouteHandler
{
protected override IHttpHandler GetHttpHandler(RequestContext requestContext)
{
var request = requestContext.HttpContext.Request;
// First attempt to match one of the posted tab types
var action = ReservationNavigationHandler.GetActionFromPostData(request);
requestContext.RouteData.Values["action"] = action.ActionName;
requestContext.RouteData.Values["viewStage"] = action.ViewStage;
return base.GetHttpHandler(requestContext);
}
The NavigationHandler actually does the job of looking in the form data but you get the idea.
This solution works, however, it feels a bit clunky and from looking at the controller class you would never know this was happening and wouldn't realise why en-gb/book would point to different methods, not to mention that this doesn't really feel that reusable.
A better solution is to have overloaded methods on the controller i.e. they are all called book in this case and then define your own custome ActionMethodSelectorAttribute. This is what the HttpPost Attribute derives from.
public class FormPostFilterAttribute : ActionMethodSelectorAttribute
{
private readonly string _elementId;
private readonly string _requiredValue;
public FormPostFilterAttribute(string elementId, string requiredValue)
{
_elementId = elementId;
_requiredValue = requiredValue;
}
public override bool IsValidForRequest(ControllerContext controllerContext, System.Reflection.MethodInfo methodInfo)
{
if (string.IsNullOrEmpty(controllerContext.HttpContext.Request.Form[_elementId]))
{
return false;
}
if (controllerContext.HttpContext.Request.Form[_elementId] != _requiredValue)
{
return false;
}
return true;
}
}
MVC calls this class when it tries to resolve the correct action method on a controller given a URL. We then declare the action methods as follows:
public ActionResult Book(HotelSummaryPostData hotelSummary)
{
return View("CustomerDetails");
}
[FormFieldFilter("stepID", "1")]
public ActionResult Book(YourDetailsPostData yourDetails, RequestedViewPostData requestedView)
{
return View(requestedView.RequestedView);
}
[FormFieldFilter("stepID", "2")]
public ActionResult Book(RoomDetailsPostData roomDetails, RequestedViewPostData requestedView)
{
return View(requestedView.RequestedView);
}
[HttpGet]
public ActionResult Book()
{
return View();
}
We have to define the hidden field stepID on the different pages so that when the forms on these pages post back to the common URL the SelectorAttributes correctly determines which action method to invoke. I was suprised that it correctly selects an action method when an identically named method exists with not attribute set, but also glad.
I haven't looked into whether you can stack these method selectors, i imagine that you can though which would make this a pretty damn cool feature in MVC.
I hope this answer is of some use to somebody other than me. :)