Adding MvcContrib SubControllers to your ASP.NET MVCProject

After a little bit of work with MVC, you get infected with the spirit of clean codeand begin to desire even more ways of eliminating repetition. You’ve got partialsand html helpers. Still you are hungry. SubControllers are the dish that will fillyou up.

Why SubControllers?

There’s a design decision here. The question is why are we designing with subcontrollers?To understand the rationale, let’s look at the qualities of the various sub-view options.

  • Partial Views – partial views are probably the most useful method for re-using viewoutput. They are very easy to set up, and are very versatile. However, they don’tcontain logic. They are intended entirely as a slave to the Action Controller. Theyget their model from the controller and simply render it. This means that the controllerneeds to know and provide everything the partial view needs. Not good for somethinglike a login status control, which is an separate concern from most controllers.
  • HTML Helpers – HTML helpers get used a lot, and they are very helpful for creatingyour own ‘controls’ to use in your pages. They do not, however, support using a viewtemplate. This means you’ve got to create them and test them with tests for emittedmarkup. This adds a lot of complexity if you are trying to do something more thancreate a html rendering function. Not a good place to insert complex view logic, likea shopping cart status widget, or anything with a table or list. The HTML helper alsostill gets it’s data from the master view/controller, so it fails at separating concerns.
  • Html.RenderAction() – RenderAction is the once and future solution to a number ofproblems. Or so I hear. I have trouble getting excited about using it right now. Currently,it is not baked into MVC, but rather is in the separate ‘MVC Futures’ assembly, whereit is unsupported. Rumor is it is buggy and unsecure. In the future it may be changedor dropped or renamed or anything. ScottGu has promised in a blog comment that itis due for inclusion in MVC 2. However, I don’t program to unreleased Microsoft products.Maybe later, but for now…
  • MvcContrib SubController – Jeff Palermo implemented subcontrollers for MvcContribto give us a working solution—now—for reusable view/controller code. Subcontrollershave their own model, ViewData, are nestable, and can use view templates for theiroutput. If you have a job that goes beyond a partial view, or a html helper, SubControllersare a peach.

Setting Up Your Project

1) Add a reference to MvcContrib.

2) Create a class called StructureMapSubControllerBinder. This is only required ifyou’re using StructureMap to do your IOC for you. You can use the base SubControllerBinderfrom MvcContrib, or create your own version for your IOC tool.

    public class StructureMapSubControllerBinder: SubControllerBinder{public override object CreateSubController(TypedestinationType){object instance = ObjectFactory.GetInstance(destinationType);if (instance == null){throw new InvalidOperationException(destinationType+ " not registered with StructureMap");}return instance;}}


    3) Make the SubControllerBinder your default binder.

    ModelBinders.Binders.DefaultBinder = new StructureMapSubControllerBinder();
    4) Add a reference to the MvcContrib namespace to the Pages section of Web.Config.This will save you putting a lot of namespace tags in your views.
    <add namespace="MvcContrib"/>

    Creating a SubController

    1) Create a ~/Controllers/SubControllers folder. This is completely optional. If youhave a bigger project you might want to make multiple subcontrollers folders for differentareas.

    2) Create a SubController class. The action needs to have the ‘same’ name as the class.It also subclasses from SubController.

    using System.Web.Mvc;using MvcContrib;namespace NWIS.Business.Web.Controllers.SubControllers{public class DemoSubController: SubController{public ViewResult Demo(){return View();}}}

    3) Create a View subfolder. Using the ‘Add View’ context menu from the controllerwon’t work because the ‘sub’ in the class name. Just create the folder yourself. ~/Views/Demo.

    4) Create a View. Right click on the ~/Views/Demo folder. Select Add->View. Namethe view ‘Demo’. Make it a partial view (.ascx). Go ahead an add some markup to theview. Whatever you like.

    Using the SubController in your View

    1) Add an attribute to your Controller class.


    2) Add the subcontroller as a parameter to the action you want to use it in.

    public ViewResultIndex(DemoSubController mySubCont)

    3) Place the subcontroller output into your view.

    <% ViewData.Get<Action>("mySubCont").Invoke();%>
    The name you use here is the name of the parameter to the controller action.

    That should be it. You subcontroller can output into your view, and you can useit in many, many controllers and actions. You can add dependencies directly to thesubcontroller in it’s constructor. You can also pass information from the action tothe subcontroller using properties.


    Adding MVC to an existing ASP.NET Application

    ASP.NET MVC Has added a very useful new programming model to developing websites in.NET. There is hype and debate all throughout the interwebs on how great MVC is. Andit all can be yours, with nothing but a ‘File->New’ in Visual Studio….unless youalready have an ASP.NET application. In which case, you need to do a bit more work.

    1. Add project references to:
    2. Create /Controllers, /Views, and /Views/Shared folders in your project
    3. Update web.config
      <?xml version="1.0" encoding="utf-8" ?><configuration><system.web><pages><namespaces><add namespace="System.Web.Mvc"/><add namespace="System.Web.Mvc.Ajax"/><add namespace="System.Web.Mvc.Html" /><add namespace="System.Web.Routing"/><add namespace="System.Linq"/><add namespace="System.Collections.Generic"/></namespaces></pages><compilation><assemblies><add assembly="System.Core,Version=,Culture=neutral,PublicKeyToken=B77A5C561934E089"/><add assembly="System.Web.Mvc,Version=,Culture=neutral,PublicKeyToken=31bf3856ad364e35" /><add assembly="System.Web.Abstractions,Version=,Culture=neutral,PublicKeyToken=31BF3856AD364E35"/><add assembly="System.Web.Routing,Version=,Culture=neutral,PublicKeyToken=31BF3856AD364E35"/></assemblies></compilation><httpModules><add name="UrlRoutingModule"type="System.Web.Routing.UrlRoutingModule,System.Web.Routing,Version=,Culture=neutral,PublicKeyToken=31BF3856AD364E35" /></httpModules></system.web><system.webServer><validation validateIntegratedModeConfiguration="false"/><modules runAllManagedModulesForAllRequests="true"><remove name="ScriptModule" /><remove name="UrlRoutingModule" /><add name="ScriptModule" preCondition="managedHandler"type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/><add name="UrlRoutingModule"type="System.Web.Routing.UrlRoutingModule,System.Web.Routing, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35" /></modules><handlers><remove name="WebServiceHandlerFactory-Integrated"/><remove name="ScriptHandlerFactory" /><remove name="ScriptHandlerFactoryAppServices" /><remove name="ScriptResource" /><remove name="MvcHttpHandler" /><remove name="UrlRoutingHandler" /><add name="ScriptHandlerFactory" verb="*" path="*.asmx"preCondition="integratedMode"type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/><add name="ScriptHandlerFactoryAppServices" verb="*"path="*_AppService.axd" preCondition="integratedMode"type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/><add name="ScriptResource" preCondition="integratedMode"verb="GET,HEAD" path="ScriptResource.axd"type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35" /><add name="MvcHttpHandler" preCondition="integratedMode"verb="*" path="*.mvc" type="System.Web.Mvc.MvcHttpHandler, System.Web.Mvc, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/><add name="UrlRoutingHandler"preCondition="integratedMode" verb="*" path="UrlRouting.axd"type="System.Web.HttpForbiddenHandler,System.Web, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" /></handlers></system.webServer></configuration>
    4. Add the following to Global.asax.cs (create a Global.asax if you don’t already haveone)
      public static void RegisterRoutes(RouteCollectionroutes){routes.IgnoreRoute("{resource}.axd/{*pathInfo}");routes.IgnoreRoute("{resource}.aspx/{*pathInfo}");routes.MapRoute("Default", //Route name"{controller}/{action}/{id}", //URL with parametersnew { controller = "Home",action = "Index", id = "" } //Parameter defaults);}protected void Application_Start(){RegisterRoutes(RouteTable.Routes);}

      The above is the “standard” routing for a MVC site. It will work, but it might causeyou trouble if you want the root of your website to still go to a ‘default.aspx’.Try this line instead:

      routes.MapRoute("Default", "MVC/{controller}/{action}/{id}", new { controller = "Home",action = "Index", id = "" }
    5. Edit your .csproj file by hand

      This will tell Visual Studio to act like this is an MVC project. You will getthe context menu items for MVC in your Controllers and Views directories.
      Note: I’ve had trouble at this point with some Visual Studio installs.If you’re having trouble with “The project type is not supported by this installation.”messages here, it may be time for a clean install in a fresh VM.
    6. Set Up IIS. If you’re using IIS7, the System.Webserver settings in your Web.Configfile should have taken care of this step. If you’re going to need to map the wildcardURL to aspnet_isapi.dll in order to get all of the MVC routing magic to work.

    7. You might want to copy of the /Views/web.config file from an existing MVC projectto prevent your views from being viewed directly, rather than through their controllers.
    8. You might also wish to create a /Scripts folder and copy over the contents ofthe /Scripts folder from native MVC project. It has the jquery and MS AJAX javascriptsthat you may be looking for if you’re following a MVC book or tutorial.

    Boy howdy. That was a good chunk of work. But now you have the infinite pleasure ofdeveloping in MVC, and your old web site should continue to work under you. Deliciousincremental development goodness.