CustomViewEngine

customviewengine.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace demo2
{
    /// <summary>
    /// From Scott Hanselman
    /// http://www.hanselman.com/blog/ABetterASPNETMVCMobileDeviceCapabilitiesViewEngine.aspx
    /// </summary>
    public class CustomViewEngine : IViewEngine
    {
        public IViewEngine BaseViewEngine { get; private set; }
        public Func<ControllerContext, bool> IsTheRightDevice { get; private set; }
        public string PathToSearch { get; private set; }

        public CustomViewEngine(Func<ControllerContext, bool> isTheRightDevice, string pathToSearch, IViewEngine baseViewEngine)
        {
            BaseViewEngine = baseViewEngine;
            IsTheRightDevice = isTheRightDevice;
            PathToSearch = pathToSearch;
        }

        public ViewEngineResult FindPartialView(ControllerContext context, string viewName, bool useCache)
        {
            if (IsTheRightDevice(context))
            {
                return BaseViewEngine.FindPartialView(context, PathToSearch + "/" + viewName, false);//switching to useCache = false to try to solve problems
            }
            return new ViewEngineResult(new string[] { }); //we found nothing and we pretend we looked nowhere
        }

        public ViewEngineResult FindView(ControllerContext context, string viewName, string masterName, bool useCache)
        {
            if (IsTheRightDevice(context))
            {
                return BaseViewEngine.FindView(context, PathToSearch + "/" + viewName, masterName, false);//switching to useCache = false to try to solve problems
            }
            return new ViewEngineResult(new string[] { }); //we found nothing and we pretend we looked nowhere
        }

        public void ReleaseView(ControllerContext controllerContext, IView view)
        {
            throw new NotImplementedException();
        }
    }

    public static class MobileHelpers
    {
        public static bool UserAgentContains(this ControllerContext c, string agentToFind)
        {
            return (c.HttpContext.Request.UserAgent.IndexOf(agentToFind, StringComparison.OrdinalIgnoreCase) > -1);
        }

        public static bool IsMobileDevice(this ControllerContext c)
        {
            return c.HttpContext.Request.Browser.IsMobileDevice;
        }

        public static bool IsTablet(this ControllerContext c)
        {
            return c.HttpContext.Request.Browser["is_tablet"].ToLower() == "true";
        }

        public static bool IsPhone(this ControllerContext c)
        {
            return IsMobileDevice(c) && c.HttpContext.Request.Browser["is_tablet"].ToLower() != "true";
        }

        public static void AddMobile<T>(this ViewEngineCollection ves, Func<ControllerContext, bool> isTheRightDevice, string pathToSearch)
            where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(isTheRightDevice, pathToSearch, new T()));
        }

        public static void AddMobile<T>(this ViewEngineCollection ves, string userAgentSubstring, string pathToSearch)
            where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(c => c.UserAgentContains(userAgentSubstring), pathToSearch, new T()));
        }

        public static void AddIPhone<T>(this ViewEngineCollection ves) //specific example helper
            where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(c => c.UserAgentContains("iPhone"), "Mobile", new T()));
        }

        public static void AddIPad<T>(this ViewEngineCollection ves) //specific example helper
           where T : IViewEngine, new()
        {
            //ves.Add(new CustomViewEngine(c => c.UserAgentContains("Firefox") || c.UserAgentContains("iPad"), "Mobile/iPad", new T()));
            ves.Add(new CustomViewEngine(c => c.UserAgentContains("iPad"), "Tablet", new T()));
        }

        public static void AddAndroidTablet<T>(this ViewEngineCollection ves) //specific example helper
           where T : IViewEngine, new()
        {
            //serve the ipad version to tablets with a screen larger than or equal to 8.9" otherwise it will fall through to the android phone one  
            //xoom is in wurfl but its physical screen size is not yet populated
            ves.Add(new CustomViewEngine(c => c.UserAgentContains("android") && (c.UserAgentContains("xoom") || GetScreenSize(c.RequestContext.HttpContext.Request.Browser) >= 226), "Tablet", new T()));
        }

        public static void AddAndroidPhone<T>(this ViewEngineCollection ves) //specific example helper
           where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(c => c.UserAgentContains("android") && GetScreenSize(c.RequestContext.HttpContext.Request.Browser) < 226, "Mobile/Droid", new T()));
        }

        public static void AddPhone<T>(this ViewEngineCollection ves)
           where T : IViewEngine, new()
        {
            //matches mobile devices with a small screen size
            ves.Add(new CustomViewEngine(c => c.IsPhone(), "Mobile", new T()));
        }

        public static void AddWP7<T>(this ViewEngineCollection ves)
          where T : IViewEngine, new()
        {
            //matches mobile devices with a small screen size
            ves.Add(new CustomViewEngine(c => c.UserAgentContains("Windows Phone OS 7") && c.UserAgentContains("IEMobile"), "Mobile/WP7", new T()));
        }

        public static void AddGenericMobile<T>(this ViewEngineCollection ves)
            where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(c => c.IsMobileDevice(), "mobile", new T()));
        }

        public static void AddIE6<T>(this ViewEngineCollection ves) //specific example helper
           where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(c => c.UserAgentContains("msie 6") || c.UserAgentContains("msie 5"), "ie", new T()));
        }

        public static void AddIELessThan9<T>(this ViewEngineCollection ves) //specific example helper
           where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(c => c.HttpContext.Request.Browser.Browser == "IE" && c.HttpContext.Request.Browser.MajorVersion < 9, "ielt9", new T()));
        }

        public static void AddBlackBerryLessThan6<T>(this ViewEngineCollection ves) //specific example helper
           where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(c => c.UserAgentContains("BlackBerry") && c.HttpContext.Request.Browser.MajorVersion < 6, "Mobile/BBlt6", new T()));
        }

        public static void AddIE<T>(this ViewEngineCollection ves) //specific example helper
           where T : IViewEngine, new()
        {
            ves.Add(new CustomViewEngine(c => c.UserAgentContains("msie"), "ie", new T()));
        }

        private static double GetScreenSize(HttpBrowserCapabilitiesBase browser)
        {
            var screenWidth = double.Parse(browser["physical_screen_width"]);//in mm
            var screenHeight = double.Parse(browser["physical_screen_height"]); //in mm
            return Math.Sqrt(Math.Pow(screenWidth, 2) + Math.Pow(screenHeight, 2));
        }
    }
}