Hey guys, I am trying to pass data in my Master page by implementing classes as below:

File: ~/Controllers/ATController.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Mvc.Ajax;
using Gateway.Library;

namespace Gateway.Controllers
{
    public abstract class ATController : Controller
    {
        protected override void Initialize(System.Web.Routing.RequestContext requestContext) {
            base.Initialize(requestContext);

            ATMenu menu = new ATMenu();
            menu.Add("Home", "Home", "Index");
            menu.Add("The Market", "Market", "Index");
            menu.Add("News & Talk", "News", "Index");
            menu.Add("The Committee", "Committee", "Index");
            menu.Add("Research & Tools", "Research", "Index");
            menu.Add("My Portfolio", "Users", "Portfolio", new List<ATPage>() { 
                new ATPage("Users", "Register"),
                new ATPage("Users", "Login")
            });

            ViewData["menu"] = menu;
        }
    }
} 

File: ~/Library/ATMenu.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace Gateway.Library {
    public class ATMenu {
        private List<ATMenuItem> _items = new List();
        public List items {
            get { return _items; }
        }
        public void Add(string title, string controller, string action) {
            this._items.Add(new ATMenuItem(title, controller, action));
        }
        public void Add(string title, string controller, string action, List pages) {
            this._items.Add(new ATMenuItem(title, controller, action, pages));
        }
    }
}

File: ~/Library/ATMenuItem.cs

using System;
using System.Collections.Generic;
namespace Gateway.Library {
    public class ATMenuItem {
        private string _title;
        public string title {
            get { return _title; }
        }
        private string _controller;
        public string controller {
            get { return _controller; }
        }
        private string _action;
        public string action {
            get { return _action; }
        }
        private List<ATPage> ActiveIn = new List();
        public ATMenuItem(string title, string controller, string action) {
            this.__MenuItem(title, controller, action);
            this.Activate(new ATPage(this.controller, this.action));
        }
        public ATMenuItem(string title, string controller, string action, List pages) {
            this.__MenuItem(title, controller, action);
            this.Activate(new ATPage(this.controller, this.action));
            if (pages.Count > 0) {
                foreach (ATPage p in pages) {
                    this.Activate(p);
                }
            }
        }
        private void __MenuItem(string title, string controller, string action) {
            this._title = title;
            this._controller = controller;
            this._action = action;
        }
        public void Activate(ATPage p) {
            if (!this.IsActiveIn(p)) {
                this.ActiveIn.Add(p);
            }
        }
        public bool IsActiveIn(ATPage p) {
            return this.ActiveIn.Contains(p);
        }
    }
}

File: ~/Library/ATPage.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace Gateway.Library {
    public class ATPage {
        private string _controller;
        public string controller { get { return _controller; } }
        private string _action;
        public string action { get { return _action; } }
        public ATPage(string controller, string action) {
            this._controller = controller;
            this._action = action;
        }
    }
}

File: ~/Views/Shared/Site.Master

<%@ Master Language="C#" Inherits="System.Web.Mvc.ViewMasterPage" %>
<%@ Import Namespace="Gateway.Library" %> 

<ul>
  <%foreach (ATMenu menu in (IEnumerable)ViewData["menu"]) { %>
    <%foreach (ATMenuItem m in menu.items) { %>
      
<%=m.title %>
    <%} %>
  <%} %>

 It compiles fine, but whenever I run the application I get the following error:

Unable to cast object of type 'Gateway.Library.ATMenu' to type 'System.Collections.Generic.IEnumerable`1[Gateway.Library.ATMenu]'.

I am sure I must be ignoring something really simple and basic. But not able to figure out as of now.

Would you be please so kind to help me out here?

Thank you

Symple answer:

Unable to cast object of type 'Gateway.Library.ATMenu' to type 'System.Collections.Generic.IEnumerable`1[Gateway.Library.ATMenu]'.

Is becouse the Gateway.Library.ATMenu is not IEnumerable. Really.

Only Gateway.Library.ATMenu.items property is IEnumerable. Right code:

<ul>
  <%foreach (ATMenu menu in (IEnumerable)((ATMenu)ViewData["menu"]).items)) { %>
    <%foreach (ATMenuItem m in menu.items) { %>
      
<%=m.title %>

    <%} %>
  <%} %>

Thanks a lot. It sure did the trick :)

Here is the final code I am using hope it proves helpful to some other newbie like me :)

<ul>
  <%foreach (ATMenuItem m in (IEnumerable)((ATMenu)ViewData["menu"]).items) { %>
    
<%=m.title %>

  <%} %>

Btw, could anyone please help me understand this concept of "Enumerable" I am having some hard time understanding well from many resources available online. Is there any explanation in very simple and easy to understand terms?

Thank you

 First: There are a lot of clases which implements IEnumerable<T> in NET Framework. Usually you don't need to implement it by yourself.

Second: There is a "C# 3.0 language specification " somewhere in msdn. It is very userfull doc.

Third: If you want to add some abilities to List<ATMenuItem> better derive from it: 

1        public class AtMenu : List<AtMenuItem> {
2            public void Add(string title, string controller, string action) {
3                Add(new AtMenuItem(title, controller, action));
4            }
5            public void Add(string title, string controller, string action, List pages) {
6                Add(new AtMenuItem(title, controller, action, pages));
7            }
8        }

1        public class AtMenuItem
2        {
3            public string Title { get; private set; }
4            public string Controller { get; private set; }
5            public string Action { get; private set; }
6        }

Fifth: There is ability to call another constructor from current:

  
1        public class AtMenuItem {
2            #region Constructors
3    
4            public AtMenuItem(string title, string controller, string action) {
5                Title = title;
6                Controller = controller;
7                Action = action;
8                this.Activate(new AtPage(this.controller, this.action));
9            }
10   
11           public AtMenuItem(string title, string controller, string action, List pages) : this(title, controller, action) {
12               if (pages.Count > 0) { // it is redundant. Better check for null.
13                   foreach (AtPage p in pages) {
14                       this.Activate(p);
15                   }
16               }
17           }
18   
19           #endregion
20   
21           #region Properties
22   
23           public string Title { get; private set; }
24           public string Controller { get; private set; }
25           public string Action { get; private set; }
26   
27           #endregion
28   
29           #region Methods
30   
31           // other methods
32   
33           #endregion
34       }
 And exists naming convention for C#.  :)

loveriysa:

Btw, could anyone please help me understand this concept of "Enumerable" I am having some hard time understanding well from many resources available online. Is there any explanation in very simple and easy to understand terms?

"Enumerable" classes collections provide an easy way to itterate through their child objects. In short, it allows you to use the foreach statement on your collection of objects.
Most of the .NET collections already provide this feature, but if you really want to create a new collection from scratch, and want to have to foreach going over it, you will need to implement the IEnumerable interface on that class.
See article below for a little more detailed information:

http://www.codeproject.com/KB/cs/csenumerators.aspx

 It is very helpful! Thanks a lot :)