MVC视图:类型参数Html帮助器DisplayFor无法从使用中推断出来

Question

我试图在此视图中使用扩展的HTML Helper DisplayFor:

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MvcCms.Web.ViewModels.SubscriptionsViewModel>" %>

<% using (Html.BeginForm("TrainingSubscription", "Account", FormMethod.Post))
    { %>
 <%: Html.DisplayFor(m => m.Subscriptions) %>
 <input type="submit" value="Save" />
 <% } %>

使用以下ViewModel

namespace MvcCms.Web.ViewModels
{
    public class SubscriptionsViewModel
    {
        public string TrainingId { get; set; }
        public string Subject { get; set; }      
        public IEnumerable<SubscriptionViewModel> Subscriptions { get; set; }

        public SubscriptionsViewModel(string TrainingId, string Subject, IEnumerable<SubscriptionViewModel> Subscriptions)
        {
            this.TrainingId = TrainingId;
            this.Subject = Subject;
            this.Subscriptions = Subscriptions;
        }
    }

    public class SubscriptionViewModel
    {
        public string ContactId { get; set; }
        public string FullName { get; set; }
        public bool Subscribed { get; set; }

        public SubscriptionViewModel(string ContactId, string FullName, bool Subscribed)
        {
            this.ContactId = ContactId;
            this.FullName = FullName;
            this.Subscribed = Subscribed;
        }
    }
}

它给了我这个错误

无法从用法中推断出方法'System.Web.Mvc.Html.DisplayExtensions.DisplayFor(System.Web.Mvc.HtmlHelper,System.Linq.Expressions.Expression>)'的类型参数.尝试显式指定类型参数

我无法弄清楚什么是错的.请注意,我能够以强类型方式访问模型,并在视图中弹出IntelliSense.但是,当我键入lambda表达式时,IntelliSense不会弹出.

Answer 1

我现在开始工作了，问题是该项目仍然使用 .NET v3.5 而不是 v4.0 编译，请参阅：

/sf/answers/499954031/