C# .NET: MultiViewController for MVC3

MultiViewController.cs

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="MultiViewController.cs" company="">
//   Nero Sule
// </copyright>
// <summary>
//   Defines the MultiViewController type.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

namespace Web.Infrastructure
{
    using System;
    using System.Linq;
    using System.Web.Mvc;
    using System.Web.Routing;

    using Norstat.Domain.Library;
    using Norstat.Log;

    /// <summary>
    /// Multi-View Controller
    /// Usage:
    /// Controller/Action/1 - HTML based on route
    /// Controller/Action.html/1 - HTML
    /// Controller/Action.json/1 - JSON
    /// Controller/Action.xml/1 - XML
    /// Controller/Action.partial/1 - partial view of action name
    /// Controller/Action.clean/1 - partial html without styling
    /// Needs routes specified in global.asax
    /// For example:
    /// Routes.MapRoute(null, "{controller}/{action}.{format}");
    /// Routes.MapRoute(null, "{controller}/{action}.{format}/{id}");
    /// </summary>
    public abstract class MultiViewController : BaseController
    {
        #region Constants and Fields

        /// <summary>
        /// Formatting key
        /// </summary>
        private const string FormatKey = "format";

        #endregion

        #region Constructors and Destructors

        /// <summary>
        /// Initializes a new instance of the <see cref="MultiViewController"/> class.
        /// </summary>
        protected MultiViewController()
        {
            this.RequestedFormat = FileFormat.Html;
        }

        #endregion

        #region Enums

        /// <summary>
        /// Possible file format
        /// </summary>
        public enum FileFormat
        {
            /// <summary>
            /// HTML type
            /// </summary>
            Html, 

            /// <summary>
            /// JSON type
            /// </summary>
            Json, 

            /// <summary>
            /// XML type
            /// </summary>
            Xml, 

            /// <summary>
            /// Partial type
            /// </summary>
            Partial, 

            /// <summary>
            /// Empty layout
            /// </summary>
            Clean
        }

        #endregion

        #region Properties

        /// <summary>
        /// Gets RequestedFormat.
        /// </summary>
        protected FileFormat RequestedFormat { get; private set; }

        #endregion

        #region Methods

        /// <summary>
        /// Formats view
        /// </summary>
        /// <param name="viewName">
        /// The view name.
        /// </param>
        /// <param name="viewModel">
        /// The view model.
        /// </param>
        /// <returns>
        /// Formatted view
        /// </returns>
        /// <exception cref="FormatException">
        /// Invalid format
        /// </exception>
        protected ActionResult FormatView(string viewName, object viewModel)
        {
            switch (this.RequestedFormat)
            {
                case FileFormat.Html:
                    if (viewName != string.Empty)
                    {
                        return View(viewName, viewModel);
                    }

                    return View(viewModel);
                case FileFormat.Json:
                    return this.Json(viewModel);
                case FileFormat.Xml:
                    return new XmlResult(viewModel);
                case FileFormat.Partial:
                    return this.PartialView(this.ControllerContext.RouteData.Values["action"] + "Partial", viewModel);
                case FileFormat.Clean:
                    if (viewName != string.Empty)
                    {
                        return this.View(viewName, "~/Views/Shared/_Clean.master", viewModel);
                    }

                    ViewResult v = View(viewModel);
                    v.MasterName = "~/Views/Shared/_Clean.Master";
                    return v;
                default:
                    throw new FormatException(
                        string.Concat("Cannot serve the content in the request format: ", this.RequestedFormat));
            }
        }

        /// <summary>
        /// Formats view
        /// </summary>
        /// <param name="viewModel">
        /// The view model.
        /// </param>
        /// <returns>
        /// Formatted view
        /// </returns>
        protected ActionResult FormatView(object viewModel)
        {
            return this.FormatView(string.Empty, viewModel);
        }

        /// <summary>
        /// Action is being executed
        /// </summary>
        /// <param name="filterContext">
        /// The filter context.
        /// </param>
        protected override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            RouteValueDictionary routeValues2 = filterContext.RouteData.Values;
            base.OnActionExecuting(filterContext);
            RouteValueDictionary routeValues = filterContext.RouteData.Values;
            if (routeValues.ContainsKey(FormatKey))
            {
                string requestedFormat = routeValues[FormatKey].ToString();
                if (IsValidFormat(requestedFormat))
                {
                    this.RequestedFormat = (FileFormat)Enum.Parse(typeof(FileFormat), requestedFormat, true);
                }
            }
        }

        /// <summary>
        /// Checks if the format is valid
        /// </summary>
        /// <param name="requestedFormat">
        /// The requested format.
        /// </param>
        /// <returns>
        /// Is format valid
        /// </returns>
        private static bool IsValidFormat(string requestedFormat)
        {
            return Enum.GetNames(typeof(FileFormat)).Any(format => format.ToLower() == requestedFormat.ToLower());
        }

        #endregion
    }
}