How to render partials from another Controller

Question

If I have a HomeController displaying its Index view, how would I proceed in order to have the Index view imbed a UserControl from another Controller?

Here's a look at the content of the Home/Index View:

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

<asp:Content ID="indexTitle" ContentPlaceHolderID="TitleContent" runat="server">
    <%=Resources.Global.HomeTitle %>
</asp:Content>

<asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server">
    <h2><%= Html.Encode(ViewData["Message"]) %></h2>
    <p><%=Resources.Global.HomeIndex %></p>

    <h3>Partial title</h3>
    <% Html.RenderPartial("~/Views/OtherController/SomeAction.ascx"); %>

</asp:Content>

Here's the OtherController content:

public class OtherController : BaseController
{
    private readonly IRepositoryContract<SomeType> repo = new SomeTypeRepository();

    public ActionResult SomeAction()
    {
        IQueryable<SomeType> items = repo.GetAllItems();
        return View("SomeAction", items);
    }
}

This gives me an NullReferenceException since the Controller is never being called by the RenderPartial() method. Changing the following line

<% Html.RenderPartial("~/Views/OtherController/SomeAction.ascx"); %>

by this

<% Html.RenderPartial("~/Views/OtherController/SomeAction.ascx",((ViewResult) new OtherController().SomeAction()).ViewData.Model); %>

works, but it sure is ugly as hell. There has to be a better way to imbed partials from another controller?

Update :: Solution found

Here's the code after implementing Adrian Grigore's solution:

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

    <asp:Content ID="indexTitle" ContentPlaceHolderID="TitleContent" runat="server">
        <%=Resources.Global.HomeTitle %>
    </asp:Content>

    <asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server">
        <h2><%= Html.Encode(ViewData["Message"]) %></h2>
        <p><%=Resources.Global.HomeIndex %></p>

        <h3>Partial title</h3>
        <% Html.RenderAction("SomeAction","OtherController"); %>

    </asp:Content>

Answer 1

Put partials used by more than one controller into the Shared folder.

The model must be passed by the page. Construct it in the controller, not in the view. Then pass it like this:

<% Html.RenderPartial("SomeAction", Model.SomeActionData); %>

Note that if Model.SomeActionData is null, then MVC will pass Model instead of Model.SomeActionData. Make sure your code can tolerate that.

Answer 2

Use the Html.RenderAction method from the ASP.NET MVC Futures library.

Answer 3

It sounds like you should have the shared UserControl in a master page (perhaps nested) so that the View doesn't need to know about controllers other than it's parent. Stephen Walther has a few good strategies for passing data to master pages and user controls.

1. Code-behind on master page (BAD)
2. ActionFilter
3. Calling the partial directly
4. Abstract base controller classes