ASP.Net MVC: Upgrading from 3.5 to 4.0, Problem with Enumerable Model

I've just ran into a big gotcha with upgrading an ASP.Net MVC app from 3.5 to 4.0. The following code works fine in 3.5, but when run in 4.0 fails with the error below:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<Estam.Web.Models.Account.SupplierBuyerViewModel>>" %>
<ul><%
    foreach (var buyer in Model)
    {
%><li>
    <%if (buyer.CanFeedback)
     { %>
    <a href="#" class="rateButton rateBuyer" name="<%=buyer.BuyerName%>" id="id_<%=buyer.BuyerId %>">
        Rate</a>
    <%} %>
    <%=buyer.BuyerName%>
</li>
<%
    }
%>
</ul>

The error:

Unable to create a constant value of type开发者_如何学JAVA 'Estam.Models.BuyerModel'. Only primitive types ('such as Int32, String, and Guid') are supported in this context.

Any help would be greatly appreciated.

PS. Here's the Model code

using System;

namespace Estam.Web.Models.Account
{
    public class SupplierBuyerViewModel
    {
        public Guid BuyerId { get; set; }
        public string BuyerName { get; set; }
        public bool CanFeedback { get; set; }
        public string PrimaryContactEmail { get; set; }

        public double Variance { get; set; }
    }
}

I think this is an Entity Framework error, so you need to go back to your database model or data access code.

Are you trying to cast an enum inside a Linq-to-Entities query? If so, try to cast it outside the query, if you can.