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

You can easily extend the WebFormViewEngine to specify all the locations you want to look in:

public class CustomViewEngine : WebFormViewEngine
{
    public CustomViewEngine()
    {
        var viewLocations =  new[] {  
            "~/Views/{1}/{0}.aspx",  
            "~/Views/{1}/{0}.ascx",  
            "~/Views/Shared/{0}.aspx",  
            "~/Views/Shared/{0}.ascx",  
            "~/AnotherPath/Views/{0}.ascx"
            // etc
        };

        this.PartialViewLocationFormats = viewLocations;
        this.ViewLocationFormats = viewLocations;
    }
}

Make sure you remember to register the view engine by modifying the Application_Start method in your Global.asax.cs

protected void Application_Start()
{
    ViewEngines.Engines.Clear();
    ViewEngines.Engines.Add(new CustomViewEngine());
}

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;
}

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);
}

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.

Most of the answers here, clear the existing locations by calling ViewEngines.Engines.Clear() and then add them back in again... there is no need to do this.

We can simply add the new locations to the existing ones, as shown below:

// note that the base class is RazorViewEngine, NOT WebFormViewEngine
public class ExpandedViewEngine : RazorViewEngine
{
    public ExpandedViewEngine()
    {
        var customViewSubfolders = new[] 
        {
            // {1} is conroller name, {0} is action name
            "~/Areas/AreaName/Views/Subfolder1/{1}/{0}.cshtml",
            "~/Areas/AreaName/Views/Subfolder1/Shared/{0}.cshtml"
        };

        var customPartialViewSubfolders = new[] 
        {
            "~/Areas/MyAreaName/Views/Subfolder1/{1}/Partials/{0}.cshtml",
            "~/Areas/MyAreaName/Views/Subfolder1/Shared/Partials/{0}.cshtml"
        };

        ViewLocationFormats = ViewLocationFormats.Union(customViewSubfolders).ToArray();
        PartialViewLocationFormats = PartialViewLocationFormats.Union(customPartialViewSubfolders).ToArray();

        // use the following if you want to extend the master locations
        // MasterLocationFormats = MasterLocationFormats.Union(new[] { "new master location" }).ToArray();   
    }
}

Now you can configure your project to use the above RazorViewEngine in Global.asax:

protected void Application_Start()
{
    ViewEngines.Engines.Add(new ExpandedViewEngine());
    // more configurations
}

See this tutoral for more info.

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();