Can I specify a custom location to “search for views” in ASP.NET MVC?

Question

I have the following layout for my mvc project:

• /Controllers
  • /Demo
  • /Demo/DemoArea1Controller
  • /Demo/DemoArea2Controller
  • etc

Answer 1

Now in MVC 6 you can implement IViewLocationExpander interface without messing around with view engines:

public class MyViewLocationExpander : IViewLocationExpander
{
    public void PopulateValues(ViewLocationExpanderContext context) {}

    public IEnumerable<string> ExpandViewLocations(ViewLocationExpanderContext context, IEnumerable<string> viewLocations)
    {
        return new[]
        {
            "/AnotherPath/Views/{1}/{0}.cshtml",
            "/AnotherPath/Views/Shared/{0}.cshtml"
        }; // add `.Union(viewLocations)` to add default locations
    }
}

where {0} is target view name, {1} - controller name and {2} - area name.

You can return your own list of locations, merge it with default viewLocations (.Union(viewLocations)) or just change them (viewLocations.Select(path => "/AnotherPath" + path)).

To register your custom view location expander in MVC, add next lines to ConfigureServices method in Startup.cs file:

public void ConfigureServices(IServiceCollection services)
{
    services.Configure<RazorViewEngineOptions>(options =>
    {
        options.ViewLocationExpanders.Add(new MyViewLocationExpander());
    });
}

Answer 2

I did it this way in MVC 5. I didn't want to clear the default locations.

Helper Class:

namespace ConKit.Helpers
{
    public static class AppStartHelper
    {
        public static void AddConKitViewLocations()
        {
            // get engine
            RazorViewEngine engine = ViewEngines.Engines.OfType<RazorViewEngine>().FirstOrDefault();
            if (engine == null)
            {
                return;
            }

            // extend view locations
            engine.ViewLocationFormats =
                engine.ViewLocationFormats.Concat(new string[] {
                    "~/Views/ConKit/{1}/{0}.cshtml",
                    "~/Views/ConKit/{0}.cshtml"
                }).ToArray();

            // extend partial view locations
            engine.PartialViewLocationFormats =
                engine.PartialViewLocationFormats.Concat(new string[] {
                    "~/Views/ConKit/{0}.cshtml"
                }).ToArray();
        }
    }
}

And then in Application_Start:

// Add ConKit View locations
ConKit.Helpers.AppStartHelper.AddConKitViewLocations();

Answer 3

Last I checked, this requires you to build your own ViewEngine. I don't know if they made it easier in RC1 though.

The basic approach I used before the first RC was, in my own ViewEngine, to split the namespace of the controller and look for folders which matched the parts.

EDIT:

Went back and found the code. Here's the general idea.

public override ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName)
{
    string ns = controllerContext.Controller.GetType().Namespace;
    string controller = controllerContext.Controller.GetType().Name.Replace("Controller", "");

    //try to find the view
    string rel = "~/Views/" +
        (
            ns == baseControllerNamespace ? "" :
            ns.Substring(baseControllerNamespace.Length + 1).Replace(".", "/") + "/"
        )
        + controller;
    string[] pathsToSearch = new string[]{
        rel+"/"+viewName+".aspx",
        rel+"/"+viewName+".ascx"
    };

    string viewPath = null;
    foreach (var path in pathsToSearch)
    {
        if (this.VirtualPathProvider.FileExists(path))
        {
            viewPath = path;
            break;
        }
    }

    if (viewPath != null)
    {
        string masterPath = null;

        //try find the master
        if (!string.IsNullOrEmpty(masterName))
        {

            string[] masterPathsToSearch = new string[]{
                rel+"/"+masterName+".master",
                "~/Views/"+ controller +"/"+ masterName+".master",
                "~/Views/Shared/"+ masterName+".master"
            };


            foreach (var path in masterPathsToSearch)
            {
                if (this.VirtualPathProvider.FileExists(path))
                {
                    masterPath = path;
                    break;
                }
            }
        }

        if (string.IsNullOrEmpty(masterName) || masterPath != null)
        {
            return new ViewEngineResult(
                this.CreateView(controllerContext, viewPath, masterPath), this);
        }
    }

    //try default implementation
    var result = base.FindView(controllerContext, viewName, masterName);
    if (result.View == null)
    {
        //add the location searched
        return new ViewEngineResult(pathsToSearch);
    }
    return result;
}

Answer 4

Note: for ASP.NET MVC 2 they have additional location paths you will need to set for views in 'Areas'.

 AreaViewLocationFormats
 AreaPartialViewLocationFormats
 AreaMasterLocationFormats

Creating a view engine for an Area is described on Phil's blog.

Note: This is for preview release 1 so is subject to change.

Answer 5

Instead of subclassing the RazorViewEngine, or replacing it outright, you can just alter existing RazorViewEngine's PartialViewLocationFormats property. This code goes in Application_Start:

System.Web.Mvc.RazorViewEngine rve = (RazorViewEngine)ViewEngines.Engines
  .Where(e=>e.GetType()==typeof(RazorViewEngine))
  .FirstOrDefault();

string[] additionalPartialViewLocations = new[] { 
  "~/Views/[YourCustomPathHere]"
};

if(rve!=null)
{
  rve.PartialViewLocationFormats = rve.PartialViewLocationFormats
    .Union( additionalPartialViewLocations )
    .ToArray();
}

Answer 6

Try something like this:

private static void RegisterViewEngines(ICollection<IViewEngine> engines)
{
    engines.Add(new WebFormViewEngine
    {
        MasterLocationFormats = new[] {"~/App/Views/Admin/{0}.master"},
        PartialViewLocationFormats = new[] {"~/App/Views/Admin//{1}/{0}.ascx"},
        ViewLocationFormats = new[] {"~/App/Views/Admin//{1}/{0}.aspx"}
    });
}

protected void Application_Start()
{
    RegisterViewEngines(ViewEngines.Engines);
}