Q:

ASP.NET MVC3 – Areas in Separate Assemblies

I am trying to set up an MVC3 solution using areas, but I want to have my areas in different assemblies.  For example, I want a parent assembly that contains shared resources like master pages, style sheets, scripts, login page, etc.  But I want distinct areas of business functionality in separate assemblies.
I tried this sample that was written for the MVC2 preview:  http://msdn.microsoft.com/en-us/library/ee307987%28VS.100%29.aspx.  (Note, I originally found this from this Stack Overflow thread:  ASP.NET MVC - separating large app).    But it appears that MVC3 does not have the option to move view files into the main project.  I’m not crazy about using the embedded resource / VirtualPathProvider option.
Any suggestions on how to make this work with MVC3?
Thanks,
Skip

A:

1 - Seperate you Mvc Areas into differrent Mvc Projects to be compiled into their own seperate assemblies
2 - Add this to your AssemblyInfo.cs class, to call a method when the application is loaded
[assembly: PreApplicationStartMethod(typeof(PluginAreaBootstrapper), "Init")]

3 - Here's what the Init method looks like when it's invoked during the load
public class PluginAreaBootstrapper
{
    public static readonly List<Assembly> PluginAssemblies = new List<Assembly>();

    public static List<string> PluginNames()
    {
        return PluginAssemblies.Select(
            pluginAssembly => pluginAssembly.GetName().Name)
            .ToList();
    }

    public static void Init()
    {
        var fullPluginPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Areas");

        foreach (var file in Directory.EnumerateFiles(fullPluginPath, "*Plugin*.dll"))
            PluginAssemblies.Add(Assembly.LoadFile(file));

        PluginAssemblies.ForEach(BuildManager.AddReferencedAssembly);
    }
}

4 - Add a custom RazorViewEngine
public class PluginRazorViewEngine : RazorViewEngine
{
    public PluginRazorViewEngine()
    {
        AreaMasterLocationFormats = new[]
        {
            "~/Areas/{2}/Views/{1}/{0}.cshtml",
            "~/Areas/{2}/Views/{1}/{0}.vbhtml",
            "~/Areas/{2}/Views/Shared/{0}.cshtml",
            "~/Areas/{2}/Views/Shared/{0}.vbhtml"
        };

        AreaPartialViewLocationFormats = new[]
        {
            "~/Areas/{2}/Views/{1}/{0}.cshtml",
            "~/Areas/{2}/Views/{1}/{0}.vbhtml",
            "~/Areas/{2}/Views/Shared/{0}.cshtml",
            "~/Areas/{2}/Views/Shared/{0}.vbhtml"
        };

        var areaViewAndPartialViewLocationFormats = new List<string>
        {
            "~/Areas/{2}/Views/{1}/{0}.cshtml",
            "~/Areas/{2}/Views/{1}/{0}.vbhtml",
            "~/Areas/{2}/Views/Shared/{0}.cshtml",
            "~/Areas/{2}/Views/Shared/{0}.vbhtml"
        };

        var partialViewLocationFormats = new List<string>
        {
            "~/Views/{1}/{0}.cshtml",
            "~/Views/{1}/{0}.vbhtml",
            "~/Views/Shared/{0}.cshtml",
            "~/Views/Shared/{0}.vbhtml"
        };

        var masterLocationFormats = new List<string>
        {
            "~/Views/{1}/{0}.cshtml",
            "~/Views/{1}/{0}.vbhtml",
            "~/Views/Shared/{0}.cshtml",
            "~/Views/Shared/{0}.vbhtml"
        };

        foreach (var plugin in PluginAreaBootstrapper.PluginNames())
        {
            masterLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/{1}/{0}.cshtml");
            masterLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/{1}/{0}.vbhtml");
            masterLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/Shared/{1}/{0}.cshtml");
            masterLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/Shared/{1}/{0}.vbhtml");

            partialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/{1}/{0}.cshtml");
            partialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/{1}/{0}.vbhtml");
            partialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/Shared/{0}.cshtml");
            partialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/Shared/{0}.vbhtml");

            areaViewAndPartialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/{1}/{0}.cshtml");
            areaViewAndPartialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Views/{1}/{0}.vbhtml");
            areaViewAndPartialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Areas/{2}/Views/{1}/{0}.cshtml");
            areaViewAndPartialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Areas/{2}/Views/{1}/{0}.vbhtml");
            areaViewAndPartialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Areas/{2}/Views/Shared/{0}.cshtml");
            areaViewAndPartialViewLocationFormats.Add(
                "~/Areas/" + plugin + "/Areas/{2}/Views/Shared/{0}.vbhtml");
        }

        ViewLocationFormats = partialViewLocationFormats.ToArray();
        MasterLocationFormats = masterLocationFormats.ToArray();
        PartialViewLocationFormats = partialViewLocationFormats.ToArray();
        AreaPartialViewLocationFormats = areaViewAndPartialViewLocationFormats.ToArray();
        AreaViewLocationFormats = areaViewAndPartialViewLocationFormats.ToArray();
    }
}

5 - Register your Areas from your different Mvc (Area) Projects
namespace MvcApplication8.Web.MyPlugin1
{
    public class MyPlugin1AreaRegistration : AreaRegistration
    {
        public override string AreaName
        {
            get { return "MyPlugin1"; }
        }

        public override void RegisterArea(AreaRegistrationContext context)
        {
            context.MapRoute(
                "MyPlugin1_default",
                "MyPlugin1/{controller}/{action}/{id}",
                new {action = "Index", id = UrlParameter.Optional}
                );
        }
    }
}

Sourcecode and additional references can can be found here: http://blog.longle.io/2012/03/29/building-a-composite-mvc3-application-with-pluggable-areas/

