Question

Suppose I have ViewModel like

public class AnotherViewModel
{
   public string Name { get; set; }
}
public class MyViewModel
{
   public string Name { get; set; }
   public AnotherViewModel Child { get; set; }
   public AnotherViewModel Child2 { get; set; }
}

In the view I can render a partial with

<% Html.RenderPartial("AnotherViewModelControl", Model.Child) %>

In the partial I’ll do

<%= Html.TextBox("Name", Model.Name) %>
or
<%= Html.TextBoxFor(x => x.Name) %>

However, the problem is that both will render name=”Name” while I need to have name=”Child.Name” in order for model binder to work properly. Or, name=”Child2.Name” when I render the second property using the same partial view.

How do I make my partial view automatically recognize the required prefix? I can pass it as a parameter but this is too inconvenient. This is even worse when I want for example to render it recursively. Is there a way to render partial views with a prefix, or, even better, with automatic reconition of the calling lambda expression so that

<% Html.RenderPartial("AnotherViewModelControl", Model.Child) %>

will automatically add correct “Child.” prefix to the generated name/id strings?

I can accept any solution, including 3-rd party view engines and libraries – I actually use Spark View Engine (I “solve” the problem using its macros) and MvcContrib, but did not find a solution there. XForms, InputBuilder, MVC v2 – any tool/insight that provide this functionality will be great.

Currently I think about coding this myself but it seems like a waste of time, I can’t believe this trivial stuff is not implemented already.

A lot of manual solutions may exists, and all of them are welcome. For example, I can force my partials to be based off IPartialViewModel<T> { public string Prefix; T Model; }. But I’d rather prefer some existing/approved solution.

UPDATE: there’s a similar question with no answer here.

Answer 1

You can extend Html helper class by this :

using System.Web.Mvc.Html


 public static MvcHtmlString PartialFor<TModel, TProperty>(this HtmlHelper<TModel> helper, System.Linq.Expressions.Expression<Func<TModel, TProperty>> expression, string partialViewName)
    {
        string name = ExpressionHelper.GetExpressionText(expression);
        object model = ModelMetadata.FromLambdaExpression(expression, helper.ViewData).Model;
        var viewData = new ViewDataDictionary(helper.ViewData)
        {
            TemplateInfo = new System.Web.Mvc.TemplateInfo
            {
                HtmlFieldPrefix = name
            }
        };

        return helper.Partial(partialViewName, model, viewData);

    }

and simply use it in your views like this :

<%= Html.PartialFor(model => model.Child, "_AnotherViewModelControl") %>

and you will see everything is ok!