ASP.NET MVC2 RenderAction makes parent loose ViewModel context

Question

I'm my Project Browser page I have 2 sub-elements that warrant their own controller (and not simply a user-control) - Upload and FileBrowser, and so I've added them using Html.RenderAction(Action, Controller, param).

The problem however, is that the Browse page requires ProjectViewModel, where Upload uses UploadViewModel, etc. etc. So by having these Html.RenderAction elements, the Browse page seems to immediately stop receiving the ProjectViewModel - i'm guessing it switches to the VM of the last RenderAction.

Is there something I have to set up in routing to ensure these already strongly typed Views keep their contexts?

Update with code:

Also, maybe I have to explicitly state that the model going TO "Upload" is a different one? I dunno.

Browser (containing Upload and FileBrowser):

<%@ 
Page Title="" 
Language="C#" 
Inherits="System.Web.Mvc.ViewPage<CKD.Web.Files.ViewModels.ProjectViewModel>"
MasterPageFile="~/Views/Project/Project.Master" 
%>

<asp:Content runat="server" ID="Main" ContentPlaceHolderID="MainContent">
    <table>
<tr>
<td id="upload" style="width: 180px" class="ui-widget ui-widget-content ui-corner-all">
    <% Html.RenderAction("Index", "Upload", new {id = Model.Project.Id}); %>
</td>
<td id="fileBrowser" style="width: auto" class="ui-widget ui-widget-content ui-corner-all">
    <% Html.RenderAction("Index", "FileBrowser", new {id = Model.Project.Id}); %>
</td>
</tr>
</table>
</asp:Content>

Upload View:

<%@ 
Page Title="" 
Language="C#" 
Inherits="System.Web.Mvc.ViewPage<CKD.Web.Files.ViewModels.UploadViewModel>" 
MasterPageFile="~/Views/Shared/Control.master"
%>
<%@ Import Namespace="System.IO" %>

<asp:Content runat="server" ID="Scripts" ContentPlaceHolderID="Scripts">
</asp:Content>

<asp:Content runat="server" ID="Main" ContentPlaceHolderID="MainContent">
<div class="uploadControl" style="Margin: 8px">
<h2 style="Margin-Bottom: 0px">Upload</h2>
<hr />

<div id="accordion" style="display: block;">
    <h3><a href="#">Files</a></h3>
    <div>
        <div class="ui-widget-content ui-corner-all" style="min-height: 80px; margin: 4px">
            <% if(Model.Files != null) %>
                <% foreach(FileInfo f in Model.Files) {%>
                    <p><%= f.Name %></p>
                    <hr />
                <% } %>
        </div>
        <ul style="width: 10px; list-style-type:none">
            <li class="ui-widget ui-widget-button ui-corners-all">Clear</li>
            <li class="ui-widget ui-widget-button ui-corners-all">Add</li>
        </ul>
    </div>
    <h3><a href="#">Transmittal</a></h3>
    <div>
        <p>File here</p>
        <p style="width: auto; margin: 8px" class="ui-widget-button">Pick File...</p>
    </div>
    <h3><a href="#">Notification</a></h3>
    <div>
        <p>
        Stuff
        </p>
    </div>
</div>
<div>
<div class="ui-widget ui-corner-all ui-widget-active">Upload Files</div>
</div>

</div>
</asp:Content>

Upload Controller:

using System.Web.Mvc;

namespace CKD.Web.Files.Controllers
{
    using System.Linq;
    using Models;
    using ViewModels;

    public class UploadController : Controller
    {
        private ICKDClientAreaRepository Repository { get; set; }
        private UploadViewModel _viewModel;

                        private UploadViewModel ViewModel
    {
        get { return _viewModel ?? (_viewModel = ViewModel = UploadViewModel.Default(Repository)); }
        set { _viewModel = value; }
    }

                    public UploadController(ICKDClientAreaRepository repository)
    {
        Repository = repository;
    }

        // GET
        public ActionResult Index(int id)
        {
            var project = Repository.Projects.Single(x => x.Id == id);
            ViewModel = UploadViewModel.ForProject(project, Repository);

            return View(ViewModel);
        }
    }
}

Upload VM:

namespace CKD.Web.Files.ViewModels
{
    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Linq;
    using System.Web.Security;
    using Models;

    public class UploadViewModel
    {
        public Project Project { get; set; }
        public DirectoryInfo Directory { get; set; }
        public User Uploader { get; set; }
        public DateTime Time { get; set; }

        public List<FileInfo> Files { get; set; }
        public FileInfo Transmittal { get; set; }

        public List<User> NotificationList { get; set; }

                        public static UploadViewModel Default(ICKDClientAreaRepository fromRepository)
    {
        var project = fromRepository.Projects.First();

        return ForProject(project, fromRepository);
    }

                                                                public static UploadViewModel ForProject(Project project, ICKDClientAreaRepository fromRepository)
    {
        var dir = project.DirectoryName;
        var uploader = fromRepository.Users.Single(x => x.Username == Membership.GetUser().UserName);
        var time = DateTime.Now;
        var notification = project.Users.ToList();

        return new UploadViewModel
        {
            Project = project,
            Directory = new DirectoryInfo(dir),
            Uploader = uploader,
            Time = time,
            NotificationList = notification
        };
    }
    }
}

Answer 1

Try making the view rendered by RenderAction() a partial view.

You should also decorate the action with [ChildActionOnly] attribute to prevent it from executing by it's own (when somebody would request http://xxx.com/Upload/Index).