ASP MVC2 Retrieving complex nested object from the form - asp.net

Question

I'm quite new to ASP MVC so maybe this is simple but I'm really stuck cause I've searched the forums with no luck ;)
I've prepared a simple example of my problem. Here's what I'm trying to do. I have the following model that I'm passing to the view:
public class SearchModel
{
public int ItemsFound { get; set; }
public int TotalItems { get; set; }
public SearchFacetModel SearchFacet { get; set; }
}
and the nested class is
public class SearchFacetModel
{
public string SearchText { get; set; }
public DateTime DateFrom { get; set; }
public DateTime DateTo { get; set; }
}
The controller looks like this
[HttpGet]
public ActionResult Index()
{
SearchModel model = new SearchModel { SearchFacet = new SearchFacetModel() { SearchText = "test", DateFrom = DateTime.Now }, ItemsFound=1, TotalItems=10 };
return View(model);
}
[HttpPost]
public ActionResult Index(SearchModel model) // Where is model.SearchFacet? Why null?
{
return View(model);
}
The view:
<% using(Html.BeginForm()) { %>
Search<br />
<%=Html.TextBoxFor(m=>m.ItemsFound) %><br />
<%=Html.TextBoxFor(m=>m.TotalItems) %><br />
Search Facet<br />
<% Html.RenderPartial("SearchFacet", Model.SearchFacet); %>
<button type=submit>Submit</button>
<%} %>
The SearchFacet control:
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<MvcApplication3.Models.SearchFacetModel>" %>
<%=Html.TextBoxFor(m=>m.DateFrom) %>
<%=Html.TextBoxFor(m=>m.DateTo) %>
<%=Html.TextBoxFor(m=>m.SearchText) %>
Now, I've already put comment near the Index method with HttpPost. I'm getting the SearchModel object but it doesn't have its SearchFacet child object. The child is null.
When I'm changing SearchFacet.ascx to accept whole SearchModel and pass it from main view then it works. But I don't want to pass whole stuff always and everywhere.
I'm surely missing something related to Model Binder but what and how to make it work my way? :)
Any help will be appreciated.
Gacu

Answer 1

The reason it doesn't work is because HTML helpers inside the partial doesn't generate proper names for the input tags. If you look at the generated source code you will see:
<input type="text" name="SearchText" id="SearchText" value="test" />
whereas it should be:
<input type="text" name="SearchFacet.SearchText" id="SearchFacet_SearchText" value="test" />
in order for the default model binder to properly map the objects in the POST action. One way to solve this is to use editor templates:
<% using(Html.BeginForm()) { %>
Search<br />
<%=Html.TextBoxFor(m=>m.ItemsFound) %><br />
<%=Html.TextBoxFor(m=>m.TotalItems) %><br />
Search Facet<br />
<%= Html.EditorFor(x => x.SearchFacet) %>
<button type=submit>Submit</button>
<%} %>
and then inside (~/Views/Home/EditorTemplates/SearchFacetModel.ascx):
<%# Control
Language="C#"
Inherits="System.Web.Mvc.ViewUserControl<MvcApplication3.Models.SearchFacetModel>" %>
<%=Html.TextBoxFor(m=>m.DateFrom) %>
<%=Html.TextBoxFor(m=>m.DateTo) %>
<%=Html.TextBoxFor(m=>m.SearchText) %>
Note that the name of the partial should be the same as the type of the property: SearchFacetModel.ascx and located inside the EditorTemplates folder.