Inspired by Heather Floyd's article (http://24days.in/umbraco-cms/2016/unique-sites-using-theming), however our use case is slightly different: we want to share a library of partials between multiple Umbraco sites with custom overrides on specific sites

PatternLibRazorViewEngine.cs

using System.Linq;
using Umbraco.Web.Mvc;

namespace Endzone.Umbraco.PatternLib
{
    public class PatternLibRazorViewEngine : RenderViewEngine
    {
        public PatternLibRazorViewEngine() : base()
        {
           /* 
            * Default partials "patterns" folder, these can be overridden simply by placing a partial with the same name in "Views/Partials"
            */
            const string patternLibViewFolder = "~/Views/_patterns";


           /* 
            * Let Umbraco's RenderViewEngine do the work, just add our partials view location to the list...
            */
            var umbracoPartialViewlocations = PartialViewLocationFormats.ToList();
            var patternLibPartialViewLocations = umbracoPartialViewlocations.Select(x => x.Replace("~/Views", patternLibViewFolder) ).ToArray();
            umbracoPartialViewlocations.AddRange(patternLibPartialViewLocations);

            PartialViewLocationFormats = umbracoPartialViewlocations.ToArray();
        }
    }
}

UmbracoEvents.cs

using System.Web.Mvc;
using Umbraco.Core;
using Umbraco.Web.Mvc;

namespace Endzone.Umbraco.PatternLib
{

    /// <summary>
    /// Registers site specific Umbraco application event handlers
    /// </summary>
    public class UmbracoEvents : ApplicationEventHandler
    {

        protected override void ApplicationStarting(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            base.ApplicationStarting(umbracoApplication, applicationContext);
            
            /* 
            * Replace the Umbraco RenderViewEngine with our PatternLibRazorViewEngine
            * this allows us to add our own View locations without too many extra steps
            */
            IViewEngine remove = null;
            ViewEngines.Engines.ForEach(x => {
                if (x.GetType() == typeof(RenderViewEngine))
                    remove = x;
            });
            if (remove != null)
                ViewEngines.Engines.Remove(remove);

            ViewEngines.Engines.Add(new PatternLibRazorViewEngine());

        }

    }
}

Hi Barry

Have you managed to use this approach on any live projects?

@smdooley : not verbatum. We have a similar concept in a base project. Are you looking for a solution to this?

@smdooley : not verbatum. We have a similar concept in a base project. Are you looking for a solution to this?

I have used http://24days.in/umbraco-cms/2016/unique-sites-using-theming for a few projects but I have experienced the occasional issue with third-party App_Plugins and routing, so I am interested to see/hear other approaches.

Is your approach compatible with the Grid Layout and Umbraco Forms?