// http://codereview.stackexchange.com/questions/110650

​

using System;

using System.Collections.Generic;

using System.Linq.Expressions;

using System.Reflection;

using System.Web.Mvc;

using System.Web.Routing;

​

namespace Kringsjaa

{

    public class UsersController : Controller

    {

        [HttpGet]

        public ActionResult Index()

        {

            var model = new UsersModel 

            {

                Name = "John Smith",

                Age = 20

            };

            return this.View(model);

        }   

​

        [HttpGet]

        public ActionResult Match(String name, Int32 age)

        {

            // TODO: Find users with similar name and/or age.

            throw new NotImplementedException();

        }

    }

    internal static class Utils

    {

​

        internal const String ControllerNameSuffix = "Controller";

​

        internal static String GetActionNameFromMethod(MethodInfo method)

        {

​

            var attribute = method.GetCustomAttribute<ActionNameAttribute>(inherit: false);

​

            if ((attribute != null) && !String.IsNullOrEmpty(attribute.Name))

            {

                return attribute.Name;

            }

​

            return method.Name;

​

        }

​

        internal static String GetControllerNameFromType(Type type)

        {

​

            if ((type.Name.Length > ControllerNameSuffix.Length) && type.Name.EndsWith(ControllerNameSuffix))

            {

                return type.Name.Substring(0, (type.Name.Length - ControllerNameSuffix.Length));

            }

​

            return type.Name;

​

        }

​

        internal static Dictionary<String, Object> GetMethodParameters(MethodCallExpression expression)

        {

​

            var dictionary = new Dictionary<String, Object>();

            ParameterInfo[] parameters = expression.Method.GetParameters();

​

            for (Int32 index = 0; (index < parameters.Length); index++)

            {

​

                Expression argument = expression.Arguments[index];

                String name = parameters[index].Name;

                Object value = Expression.Lambda(Expression.Convert(argument, argument.Type)).Compile().DynamicInvoke();

​

                dictionary.Add(name, value);

​

            }

​

            return dictionary;

​

        }

​

    }

    internal sealed class ActionInfo

    {

​

        private String actionName;

        private String controllerName;

        private RouteValueDictionary routeValues;

​

        private ActionInfo()

        {

        }

​

        public String ActionName

        {

            get

            {

                return this.actionName;

            }

        }

​

        public String ControllerName

        {

            get

            {

                return this.controllerName;

            }

        }

​

        public RouteValueDictionary RouteValues

        {

            get

            {

                return this.routeValues;

            }

        }

​

        internal static ActionInfo Create<TController>(Expression<Func<TController, ActionResult>> expression) where TController : Controller

        {

​

            if (expression == null)

            {

                throw new ArgumentNullException("expression");

            }

​

            var body = (MethodCallExpression)expression.Body;

            var routeValues = new RouteValueDictionary(Utils.GetMethodParameters(body));

            String actionName = Utils.GetActionNameFromMethod(body.Method);

            String controllerName = Utils.GetControllerNameFromType(typeof(TController));

​

            return new ActionInfo

            {

                actionName = actionName,

                controllerName = controllerName,

                routeValues = routeValues

            };

​

        }

​

    }

    public static class MvcExtensions

    {

​

        public static String Action<TController>(this UrlHelper urlHelper, Expression<Func<TController, ActionResult>> expression) where TController : Controller

        {

​

            if (urlHelper == null)

            {

                throw new ArgumentNullException("urlHelper");

            }

            else if (expression == null)

            {

                throw new ArgumentNullException("expression");

            }

​

            var info = ActionInfo.Create(expression);

​

            if (info.RouteValues.Count == 0)

            {

                return urlHelper.Action(info.ActionName, info.ControllerName);

            }

​

            return urlHelper.Action(info.ActionName, info.ControllerName, info.RouteValues);

​

        }

​

    }   

}