Extension to render partials of nested models with correct element name prefix

_PartialExtension.cs

using System;
using System.Linq.Expressions;
using System.Web.Mvc;
using System.Web.Mvc.Html;

public static class PartialExtension
{
    public static MvcHtmlString PartialFor<TModel, TValue>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression)
    {
        return html.PartialFor(typeof (TValue).Name, expression);
    }

    public static MvcHtmlString PartialFor<TModel, TValue>(this HtmlHelper<TModel> html, string partialViewName, Expression<Func<TModel, TValue>> expression)
    {
        var containingModel = html.ViewData.Model;
        var model = expression.Compile()(containingModel);

        var oldTemplateInfo = html.ViewData.TemplateInfo;
        var newViewData = new ViewDataDictionary(html.ViewData)
        {
            TemplateInfo = new TemplateInfo
            {
                FormattedModelValue = oldTemplateInfo.FormattedModelValue,
            }
        };

        var newPrefix = ExpressionHelper.GetExpressionText(expression);
        if (oldTemplateInfo.HtmlFieldPrefix.Length > 0)
        {
            newPrefix = oldTemplateInfo.HtmlFieldPrefix + "." + newPrefix;
        }
        newViewData.TemplateInfo.HtmlFieldPrefix = newPrefix;

        return html.Partial(partialViewName, model, newViewData);
    }
}

Example AddressFields.cshtml

@model gts.Web.Models.AddressFields
           
<ul>
    <li>
        @Html.HumanLabelFor(x => x.Line1)
        @Html.TextBoxFor(x => x.Line1)
        @Html.ValidationMessageFor(x => x.Line1)
    </li>
    <li>
        @Html.HumanLabelFor(x => x.Line2)
        @Html.TextBoxFor(x => x.Line2)
        @Html.ValidationMessageFor(x => x.Line2)
    </li>
    <li>
        @Html.HumanLabelFor(x => x.Line3)
        @Html.TextBoxFor(x => x.Line3)
        @Html.ValidationMessageFor(x => x.Line3)
    </li>
    <li>
        @Html.HumanLabelFor(x => x.Town)
        @Html.TextBoxFor(x => x.Town)
        @Html.ValidationMessageFor(x => x.Town)
    </li>
    <li>
        @Html.HumanLabelFor(x => x.Postcode)
        @Html.TextBoxFor(x => x.Postcode)
        @Html.ValidationMessageFor(x => x.Postcode)
    </li>
</ul>

Example ContactPointFields.cshtml

@model gts.Web.Models.ContactPointFields

@Html.PartialFor(x=>x.Address)
<ul>
    <li>
        @Html.HumanLabelFor(x => x.EmailAddress)
        @Html.TextBoxFor(x => x.EmailAddress)
        @Html.ValidationMessageFor(x => x.EmailAddress)
    </li>
    <li>
        @Html.HumanLabelFor(x => x.TelephoneNumber)
        @Html.TextBoxFor(x => x.TelephoneNumber)
        @Html.ValidationMessageFor(x => x.TelephoneNumber)
    </li>
</ul>

Example Model.cs

public class OrganisationFields
{
    public string Name { get; set; }
    public ContactPointFields ContactPoint { get; set; }
}

public class AddressFields
{
    public string Line1 { get; set; }
    public string Line2 { get; set; }
    public string Line3 { get; set; }
    public string Town { get; set; }
    public string Postcode { get; set; }
}

public class ContactPointFields
{
    public AddressFields Address { get; set; }
    public string EmailAddress { get; set; }
    public string TelephoneNumber { get; set; }
}

Example OrganisationFields.cshtml

@model gts.Web.Models.OrganisationFields

<ul>
    <li>
        @Html.HumanLabelFor(x => x.Name)
        @Html.TextBoxFor(x => x.Name)
        @Html.ValidationMessageFor(x => x.Name)
    </li>
</ul>
@Html.PartialFor(x => x.ContactPoint)

Example Output.html

...
<input id="ContactPoint_Address_Postcode" type="text" value="" name="ContactPoint.Address.Postcode">