passing an object to a view

Mordr8d · October 20th, 2010, 10:37 AM

Hi. I'm following your book as my guideline to MVC2 (since i'm learning it).
I had an object and want to passe from a controller to a view.
My object has 3 other objects on it as:

Code:

public class MenuContainer 
    {
        public List<Menu> Containers = new List<Menu>();
    }
    public class Menu
    {
        public string title { get; set; }
        public List<MenuItem> Items = new List<MenuItem>();

    }
    public class MenuItem
    {
        public string description { get; set; }
        public string url { get; set; }
    }
}

Now i neet to pass my final object (MenuContainer ) to a view. On the view i mys get several values from "sub-objecs".
Now... as it has been said on chapter 6, pag. 285, i had this to my view:

Code:

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MenuContainer>" %>

The solution is build but its to be rendered on browser i get this:

Compiler Error Message: CS0246: The type or namespace name 'MenuContainer' could not be found (are you missing a using directive or an assembly reference?)

flyinhawaiian · October 20th, 2010, 12:21 PM

I believe you need to specify full namespace in your view. Look for "namespace" in your class. So your view code should look something like this:

Code:

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<YourProject.Models.MenuContainer>" %>

Mordr8d · October 21st, 2010, 04:46 AM

you right.

"<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<NerdDinner.Model s.MenuContainer>" %>
"

Mordr8d · October 21st, 2010, 05:45 AM

As i said before, I had this:

Code:

public class MenuContainer 
    {
        public List<Menu> Containers = new List<Menu>();
    }
    public class Menu
    {
        public string title { get; set; }
        public List<MenuItem> Items = new List<MenuItem>();

    }
    public class MenuItem
    {
        public string description { get; set; }
        public string url { get; set; }
    }
}

When i'm trying iterate on view:

Code:

foreach(NerdDinner.Models.MenuContainer xpto in Model) 
                   {%>

i had an error about bad implementation on IENumerator implementation. can someone guide me on this:

Code:

    public class MenuContainer : IEnumerator
    {

        public List<Menu> Containers = new List<Menu>();

        private int Position = -1;

        public IEnumerator GetEnumerator()
        {
            return (IEnumerator)this;
        }

        ///
        public bool MoveNext()
        {
            if (Position < Containers.Count - 1)
            {
                ++Position;
                return true;
            }
            return false;
        }

        public void Reset()
        {
            Position = -1;
        }


        public object Current
        {
            get
            {
                if (Position < 0)
                    throw new InvalidOperationException();
                if (Position > Containers.Count)
                    throw new InvalidOperationException();
                return this.Containers;
            }
        }
    }
    
    /// <summary>
    /// Classe que contÃ©m sub-menu (e os submenu itens relativos a estes)
    /// </summary>
    public class Menu 
    {
        public string title { get; set; }
        public List<MenuItem> Items = new List<MenuItem>();
    }

    /// <summary>
    /// Classe que representa os items dos sub-menus - descriÃ§Ã£o e url (como Ã© mvc isto deverÃ¡ ser alterado para reflectir
    ///  uma view numa fase posteriormente
    /// </summary>
    public class MenuItem
    {
        public string description { get; set; }
        public string url { get; set; }
    }

I need to iterate all objects in order to get their values in my value.
One step at the time, but i'm stuck arounde here now.

flyinhawaiian · October 21st, 2010, 10:43 AM

So far this code looks OK. I think the problem may be somewhere else. Show us your Model code.

Mordr8d · October 25th, 2010, 12:56 PM

my first code was wrong. to iterate the right code is this:

<ul class="dropdownmenu">
<% foreach (NerdDinner.Models.Menu m in Model.Containers)
{%>
<li class="mainmenu">
<div id="xpto"><%: m.title %></div>
<ul class="submenu" id="xpto2">
<%foreach (NerdDinner.Models.MenuItem mItem in m.Items)
{%>
<li>
dasda
<%: Html.ActionLink(mItem.description,mItem.view, mItem.controler ) %>

</li>
<% } %>
</ul>
</li>
<%}%>
</ul>

Mordr8d · October 25th, 2010, 01:07 PM

After i get this work. i realize that, since i want to use this object as root for a menu, the iteration on object must be done outside a view, since, if i get from the view, i'll lost the object passed to it by parameter.

I had two diferente ideias but got stuck on both. First was to use a partial view (i didn't get to have any reference to my xml object there) - why?!

My second try was to pass the object to a viewdata and called it on site.master directly. Which is the best aproach?

I follow the 2nd one and got stuck, since i can't convert from the viewdata object to my object it self, or i can but having this error:
" Message=Unable to cast object of type 'NerdDinner.Models.MenuContainer' to type 'System.Collections.Generic.IEnumerable`1[NerdDinner.Models.MenuContainer]'.
"

This happens when on my site.master i do this:

Code:

    <% foreach (NerdDinner.Models.MenuContainer varc in (IEnumerable<NerdDinner.Models.MenuContainer>)ViewData["XmlDoc"])
                   {%> 

                   
                   <%}
                           
                           
                %>

I had posted a similar doubt on asp.net foruns, btw.

flyinhawaiian · October 25th, 2010, 01:30 PM

Seems beyond the scope of this forum. Maybe your ViewData["XmlDoc"] isn't really a MenuContainer? Can't tell because we have no idea what you did to set this in the controller.

flyinhawaiian · October 25th, 2010, 01:35 PM

Oh, might not be casting correctly. See this example.