RenderUserControl from Controller

Ran into a situation today where I wanted to render a ViewUserControl from my controller.  I had a couple of hard times getting this done with the Microsoft MVC CTP1, but finally have it working.  We did this to support using the Prototype observe to get behavior similar to a cascading drop down.

ASPX View Page

 <% using (Html.Form<Web.Controllers.PlaqueOrderController>

          (action => action.Create())) { %>  

  Season: 

    <p> 

       <%= Html.Select("SeasonId", ViewData.Seasons, "Name", "Id")%>  

    </p> 

  Statistic: 

  <div name="statistic" id="statistic"> 

    <p>

      <select disabled="disabled">

        <option>Select Sport</option>

      </select>

    </p>

  </div>

 <% } %>

 <script type="text/javascript"> 

   Event.observe("SeasonId", "change", function() { 

          new Ajax.Updater('statistic', '/PlaqueOrder/GetStatistics/'

                           + $F("SeasonId")) }); 

 </script>

 

This will observe the season drop down and when it is changed call the PlaqueOrder controller's GetStatistics action passing the selected SeasonId to the action. The action in the controller then looks like this.  I should mention that I'm using LLBLGen for the ORMapper here.

 

PlaqueOrderController

[ControllerAction]

public void GetStatistics(int id) 

{ 

   SeasonEntity season = new SeasonEntity(id); 

   HtmlHelper helper = new HtmlHelper(

                             new ViewContext(this.ControllerContext, 

                                             this.ViewData, 

                                             this.TempData));

   string html = helper.RenderUserControl(

                       "/Views/PlaqueOrder/Statistic.ascx", season);

   Response.Write(html); 

}

 

We had to give the absolute path to the RenderUserControl because we kept getting The relative virtual path 'Statistic' is not allowed here when we used helper.RenderUserControl("Statistic").  We also had to use Response.Write to get the html created from the ViewUserControl to the browser to replace the innerHtml of the statistic div.  Next is the ViewUserControl.

 

Statistic.ascx

<%@ Control Language="C#" AutoEventWireup="true"

    CodeBehind="Statistic.ascx.cs" 

    Inherits="Web.Views.PlaqueOrder.Statistic" %>

<%= Html.Select("StatisticId", 

                ViewData.Sport.Statistics, "Name", "Id")%> 

 

And here is the codebehind that types the ViewUserControl to the Season that we are passing as the ControlData.

 

Statistic.ascx.cs

namespace Web.Views.PlaqueOrder 

{ 

   public partial class Statistic : 

                 System.Web.Mvc.ViewUserControl<SeasonEntity> 

   { } 

}

 

We had a hard time find much information how to do this.  I'm sure there are other ways to accomplish this, but to us being able to render a ViewUserControl from a Controller is helpful with how we have used Prototype for AJAX communication.

Comments

[Nik]

Hi there.

With the latest drop of MVC, this no longer works, as you need to pass in additional parameters ( viewName, and masterName) ... any ideas?

all the best.

[bclubb]

I'll take a look and see if sending two blank strings would work. We've actually started to use only viewusercontrols for pages and even as the master pages so we make this call from an application controller that implements renderview and uses this call to load the view as a viewusercontrol. From here we have the thew viewname and we pass it to the helper.

I don't see any need to know the view when rendering the usercontrol so I would think that passing an empty string for both values should be fine.