model-view-controller - MVC View : Type arguments Html helper DisplayFor cannot be inferred from the usage

Question

我正在尝试在此 View 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

The type arguments for method 'System.Web.Mvc.Html.DisplayExtensions.DisplayFor(System.Web.Mvc.HtmlHelper, System.Linq.Expressions.Expression>)' cannot be inferred from the usage. Try specifying the type arguments explicitly

我无法弄清楚出了什么问题。请注意，我可以在 View 中弹出 IntelliSense 的情况下以强类型方式访问模型。但是，当我输入 lambda 表达式时，IntelliSense 没有弹出。

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:

https://stackoverflow.com/a/7142200/1232507