Base Contoller Get Value

Question

I having trouble getting a value to my base controller. All I would like to do is have my base contoller pick up a ID from an ActionLink?

Link

<%= Html.ActionLink("About Us", "About", new { SectionId = 1 })%>

Base Controller

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

namespace Website.Controllers
{
    public class SectionController : Controller
    {
        //
        // GET: /Section/

        public SectionController(int SectionId)
        {
            if (SectionId == 1)
            {
                ViewData["Message"] = "GOT AN ID";
            }
            else
            {
                ViewData["Message"] = "NO ID";
            }
        }
    }
}

Home Controller

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

namespace Website.Controllers
{
    [HandleError]
    public class HomeController : SectionController
    {
        public ActionResult Index()
        {
            return View();
        }

        public ActionResult About()
        {
            return View();
        }


        public ActionResult Contact()
        {
            return View();
        }

   }
}

Solution so far

ActionLink

<%= Html.ActionLink("About Us", "About", new { SectionId = 1})%>

SectionAttribute.cs

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

namespace Website.ActionFilters
{
    public class SectionAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
        // Actions have sectionId parameter
        object SectionId = filterContext.ActionParameters.FirstOrDefault(x => x.Key == "SectionId").Value;

            if (SectionId != null && (int)SectionId == 1)
            {
                filterContext.Controller.ViewData["Message"] = "GOT AN ID";
            }
            else
            {
                filterContext.Controller.ViewData["Message"] = "NO ID";
            }
        }
    }
}

SectionController

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

namespace Website.Controllers
{
    [Section]
    public class SectionController : Controller
    {
    }
}

View

<%= Html.Encode(ViewData["Message"]) %>

Answer 1

A constructor of a base controller is not typically the place where common code is placed. You usually create a filter for common code. If you decorate the base controller with this filter attribute, then all inheriting controllers use that filter.

Answer 2

Your code won't work. Instead you should define OnActionExecuting method in base controller, where you get actual sectionId from route data and set ViewData accordingly. Try something like this (not tested):

public class SectionController : Controller
{
    protected override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        // Actions have no sectionId parameter - look for it in querystring
        string SectionId = filterContext.HttpContext.Request.QueryString["sectionId"];

        int sId;

        if (int.TryParse(SectionId, out sId) && sID == 1)
        {
            filterContext.Controller.ViewData["Message"] = "GOT AN ID";
        }
        else
        {
            filterContext.Controller.ViewData["Message"] = "NO ID";
        }
    }
}

Updated:

You can move this out from controller and create ActionFilter. It is very simple:

public class SectionAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        // Actions have sectionId parameter
        object SectionId = filterContext.ActionParameters
            .FirstOrDefault(x => x.Key == "sectionId").Value;

        if (SectionId != null && (int)SectionID == 1)
        {
            filterContext.Controller.ViewData["Message"] = "GOT AN ID";
        }
        else
        {
            filterContext.Controller.ViewData["Message"] = "NO ID";
        }
    }
}

...

[Section]
public class SectionController : Controller {

or

[HandleError, Section]
public class HomeController : SectionController {