I'd like to get access to the current executing Controller so I can offload the return of the appropriate ActionResult onto a helper method. To this end, I'm looking for the equivalent of what I would have thought would be ControllerContext.Current but isn't. Thanks!
Edit for clarification: I've got a generic form control which is JavaScript-based but I'd like to add an option so that it works with noscript. At the moment my Controller sets the ViewData.Model to a JSON-ified Models.FormResponse<T>.
This FormReponse is set up with the status of the post and any error messages that were generated, so I'd like a GetActionResult() method which does the script/noscript check (a hidden form input) and either:
Sets the Model to the JSONed FormResponse and returns a View(), or
Serializes the FormResponse to the Session and returns a Redirect().
As this obviously changes the return value and I don't want to do the check myself every time, I need to call View or Redirect from the FormResponse's GetActionResult method in order to call this as:
return formResponse.GetActionResult();
I know with a more astronautical design this could be made even more robust but as the noscript option is not a major feature at the moment, I just need to get a quick solution working that doesn't break other things.
Update #2
The following, implemented in an ActionResult class, does the job for me. Thanks CVertex!
public override void ExecuteResult(ControllerContext context)
{
if (CMSEnvironment.NoScript)
{
Oracle.Response.Redirect(Oracle.Request.UrlReferrer.ToString(), true);
}
context.Controller.ViewData.Model = _model.ToJSON();
new ViewResult()
{
ViewName = Areas.Site.Helpers.SharedView.Service,
ViewData = context.Controller.ViewData
}.ExecuteResult(context);
}
Statics are bad for testability, and very much discouraged in MVC.
Why do you want to access the current controller and action method?
The best way to do this is to implement your own ActionFilter.
This gives you a means of intercepting requests before or after actions methods execute.
EDIT:
By intercepting the result inside OnActionExecuted of a filter, you can do your noscript/script checks and modify your ViewData accordingly for consumption by the View.
Inside OnActionExecuted, you can also do the noscript check and have complete control over the final ActionResult or the ViewData, as you please.
Or, you can write your own ActionResult that makes all these decisions.
So, your controller action ultimately does
return new MyActionResult(format_and_view_agnostic_model_object);
There doesn't appear to be a way to navigate to the current Controller from a thread. That is you could get the ControllerBuilder and you can get the MvcHttpHandler but neither then lets you access the controller instance that the handler is using.
Related
In the process of updating a C# MVC 2.0 application!
I have a view “Signup” and another view “ForgotPassword”.
Each view have a with a submit button.
Each form is submitted to the same Controller but to two different ActionResult:
[HttpPost]
public ActionResult Signup(SignupModel signupModel)
{…}
[HttpPost]
public ActionResult ForgotPwd(ForgotPasswordModel forgotPasswordModel)
{…}
Upon completion my goal is to redirect the user to a “thankyou” page but based on where the user is coming from (either Signup or ForgotPassword) I wish to display a particular message (or a different UI).
Inside the same Controller, I created a “Thankyou” ActionResult:
public ViewResult Thankyou()
{
return View();
}
I was thinking of adding a parameter to my Thankyou() method which would allow me to know where the user is coming from (Signup or ForgotPwd). From there, make the “thankyou” page display the appropriate UI/message.
I’m looking for a clean and simple solution.
Should I create two View User Controls and show the appropriate one based on the parameter being passed?
In addition, instead of having an “ActionResult” for my Thankyou() method couldn’t I use a “PartialViewResult” ?
EDIT:
I was actually considering something along those lines…
Where ThankyouType is an Enum.
[HttpPost]
public ActionResult Signup(SignupModel signupModel)
{
//Validation code...
return View("Thankyou", ThankyouType.SignupDone);
}
[HttpPost]
public ActionResult ForgotPassword(ForgotPasswordModel forgotPasswordModel)
{
//Validation code...
return View("Thankyou", ThankyouType.ForgotPasswordDone);
}
And then have my “Thankyou” ViewResult like this:
public ViewResult Thankyou(ThankyouType type)
{
return View(type);
}
Doesn’t seem like I can create a strongly typed view based on Enum (unless I’m wrong).
Perhaps I’ll read more on PartialViewResults and/or find examples…but then again, I could be completely wrong.
I would personally give the ThankYou view a model that has the message you want to display, and have your two controller actions render the ThankYou view directly on success rather than calling a ThankYou action.
However, if you're sure you want a redirect, you may consider using the TempData collection to store a message or a key of some kind. The ThankYou controller can then retrieve this value and pass it to the View. This situation is what TempData was made for.
Edit
There's no reason you shouldn't be able to use an enum value as your model type, but if that gives you trouble you should at least be able to create a model type that has an enum property on it.
The strategy of sending the ThankYouType as part of the redirect request would work just fine, if that's what you prefer. The only potential downside is that it would look like this in the URL:
http://domain.com/controller/ThankYou?type=ForgotPasswordDone
I have no real arguments against it. There are lots of options. Use the one that feels best to you.
I have an ExcelResult action result that returns Microsoft Excel documents, based off the Stephen Walther tip. Basically it just writes a stream out to the Response. When debugging VS 2010 (ASP.NET Dev Server), it runs fine, but when I run it on an IIS 6 box, I get the following error:
The view 'GenerateExcel' or its master was not found. The following locations were searched:
~/Views/Home/GenerateExcel.aspx
~/Views/Home/GenerateExcel.ascx
~/Views/Shared/GenerateExcel.aspx
~/Views/Shared/GenerateExcel.ascx
There is no associated View, and therefore no file, but there shouldn't have to be. What am I doing wrong?
UPDATE
By simply returning void instead of an ActionResult, I no longer have this issue. Instead of returning the ExcelResult, I'm explicitly calling it's ExecuteResult method, which is writing to the output stream.
Before
public ActionResult GenerateExcel()
{
return this.Excel(parameters);
}
After
public void GenerateExcel()
{
ExcelResult excelResult = this.Excel(parameters);
excelResult.ExecuteResult(null);
}
After that, I had security issues with my NTLM authentication, but they 'went away' (meaning I expect them to come back). For now, though, everything is working properly.
Make sure your action method does not return a ActionResult:
public void DoSomething()
I didn't look at the code for the action result in much detail, but there must be something wrong with your action result. Did you inherit from some other action result as opposed to the ActionResult class? Did you call base.ExecuteResult? If so, that would explain why it is looking for the view. I have created several custom controller actions to return various file types and they never look for a view.
I agree with the comments on the answer saying to return void. That definitely is a hack. You should not call ExecuteResult from inside your action. You are basically writing directly to the response stream from your controller action. Obviously it works but it really doesn't fit the MVC model.
Is it possible in ASP.NET MVC via some extension/override points to allow a "delegate field" to be used as an "action"?
Something like:
using System;
using System.Web.Mvc;
namespace Company.Web.Controllers
{
public class SwitchboardController : BaseController
{
public Func<ActionResult> Index, Admin, Data, Reports;
public SwitchboardController()
{
// Generic views
Index = Admin = Data = Reports =
() => View();
}
}
}
I know I'm a little hell-bent for this one but if this is possible it'd open up many new ways of making actions. You could, for example, have Django-style generic views in MVC with only a single line of code to define the action or have different ways to factor duplicate logic across multiple controllers.
I'm not quiet sure where would be the place to slap this logic into or how much work would be required to alter something so fundamental in the framework.
You will probably have to build your own Controller factory. This class builds controllers, and implements IControllerFactory. You can inherit from DefaultControllerFactory. Override CreateController() to return your own IController.
Register your controller factory in Application_Start() of MvcApplication using this line:
ControllerBuilder.Current.SetControllerFactory(typeof(MyControllerFactory));
In your implementation of IController, override the Execute method. You can use the RequestContext to decide which delegate to invoke. It would probably be easiest to inherit from ControllerBase, and override Execute in there if you don't want to fully implement IController.
The RequestContext passed into Execute carries a RouteData object. This is a dictionary populated by the routing engine that tells you what action should be invoked, and any parameters. You can get the action name like this:
//context is a RequestContext object passed to IController.Execute()
string actionName = requestContext.RouteData.Values["action"];
You could even define your action as a dictionary, and just pull them out once you get the action name.
One last thing, normal action methods return an ActionResult, which the framework uses to decide which view to render. Once you execute your delegates, I think you'll have to set some stuff manually in your special base controller. I'm not exactly sure what to set or how to get your View executed from here without cracking open the MVC source.
Good luck! This looks like an interesting idea.
As you seem to be implementing a BaseController in your code sample, if you override the Execute (from the IController) you'll be able to interpret the request => action however you like.
No, it isn't. The base controller is looking for methods and not for fields to dispatch an action.
EDIT:
Sorry, I was a bit fast and fixed to the standard classes provided.
You can do that but you have to overwrite the Execute Method in your controller or implement and provide your own IActionInvoker to dispatch the action to fields. Look into the post action processing in detail. It explains the dispatching in detail.
I have a value which I want to be vaild during a single request. I am not using Session, as this would make the value global for the entire navigation session.
So I have put thie value in a static field of a class. Great, but then I discovered that such fields are even more global, that is, they stay set for the entire application! This means that there could be random interaction among navigation sessions.
So the question is: is there a safe place I can put a global variable, which will be
global throughout the request
reset after the request is completed
not affected by any other request, either of the same user or by other users
Thanks
Palantir
EDIT
I'll elaborate. I have a piece of code in my master page, which I need to hide on certain conditions, of which I am aware in the controller only. I thought about setting a static variable in the controller, which then would be queried by the master page, but now I see there could be a better way...
Use HttpContext.Items - a per-request cache store. Check out this article on 4guysfromrolla for more details.
It should work fine in ASP.NET MVC. You may wish to derive your master page from a base class (either via code-behind or using the Inherits directive) and have a protected method on the base class that inspects HttpContext.Items and returns, e.g. true/false depending whether you want to display the conditional code.
TempData lasts until the next request as already noted.
But there are also two other dictionaries scoped to the single request.
{Controller,ViewPage}.ViewData
Context.Items
To communicate from controller to (master) page ViewData is probably the better choice.
Two approaches come to mind:
Create a base controller where you set this variable, and then have all your controllers inherit from that.
Use TempData - the problem here being that it sticks around for the next request. But maybe knowing that, you can work around it by using a GUID key to determine that you are, in fact, getting a new value when you need it.
I would probably go with 1).
The common way to access data in a MasterPage that is set in Controller (Action) is via ViewData["TheDataKey"] = "SomeValue".
This is relatively easy and there are a couple of ways that you can do it - depending on how your site works.
I'm interpreting your request as that you want a property or variable that exists for the duration of the request and is visible to the controller, model and master.
A static property is visible to the current application in ASP this means a load of users connecting at once, but not necessarily all of them. IIS will spawn new ASP applications as it needs to.
So the ways you can do this:
You can have a custom base class for your master page or a code-behind page (as all the WebForms stuff still works)
You can have a custom base class for your controllers.
You can get to one from the other, so:
void Page_Init( object sender, EventArgs e )
{
var ctrl = this.ViewContext.Controller as MyBaseController;
if ( ctrl != null )
{
MyLocalProp = ctrl.PropOnMyController;
}
}
This will then be available in the controller and the master page on a per Request basis.
Did you look into the tempData that is attached to the controller class? it is a simple dictionary that preserves it's value through one single request.That would meant that your data can only be accessed in the controller but that should not be a problem.
public class MyController : Controller
{
[AcceptVerbs(HttpVerbs.Get)]
public ActionResult MyAction(string id)
{
this.TempData["Message"] = "YourData";
}
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult MyAction(string Id)
{
var myData = this.TempData["Message"];
}
}
This works for me. I use it only to display warning messages and stuff like that.
What is the point of an action returning ActionResult?
Returning an ActionResult instead of "just doing whatever the ActionResult is doing" (i.e. using Response.Redirect directly or trying to render out a View through the Response OutputStream directly) gives you one really nice advantage: Unit Testing is really easy on that, especially since you normally do not need a web server to unit test MVC Projects.
Addendum: As an example for a redirect:
If you do
return Redirect(newUrl);
in your controller, your Unit Test can now
Verify that the return value is of Type "RedirectResult"
Look at the URL that is being redirected to by checking result.Url after casting it to RedirectResult
All without having to spin up IIS or trying to "clevery" intercept the Response.Redirect call
At the end of the day, RedirectResult calls Response.Redirect in it's ExecuteResult function, but your Controller Unit Test sits in front of that
Addendum 2: And while I am on it, here is an example of a Custom ActionResult:
http://www.stum.de/2008/10/22/permanentredirectresult/
This is just to show that they are not "Black Magic". They are actually pretty simple: Your Controller returns an Action Result, and the MVC Runtime will eventually call the ExecuteResult function on it, passing in a ControllerContext that your ActionResult can interact with. The whole point again is to separate the parts of M-V-C, to make Code Reusable, and to make Unit testing easier, or in short: To give a very clean Framework.
Since it is the base class, it allows you to return any of the ActionResult subclasses, such as ViewResult or JsonResult. I typically return ViewResult as the default, but override that behavior if I am dealing with Ajax to return a JsonResult object.
This allows me to add Ajax as a progressive enhancement and keep the application working without JavaScript and without the need for separate controller actions.
ActionResult is the base class for many different types of controller results. By returning the base class, the controller action can return different types of results depending on the outcome of the method -- a ViewResult, a RedirectToActionResult, etc. ActionResult contains all of the data needed by the View or new Action that is the result of the current controller action.