MVC2.0 中UpdateModel为什么不能更新数据

Question

最近在看MVC 2.0，想通过实例Nerddinner来了解整个设计模式，在更新数据时遇到了问题，UpdateModel好象不能更新数据了,怎么回事？

这是DinnerController里的代码 
// GET: /Dinners/Edit/5
 
    public ActionResult Edit(int id)
    {
      Dinner dinner = dinnerrepository.GetDinner(id);
      return View(new DinnerFormViewModel(dinner));
    }

    //
    // POST: /Dinners/Edit/5

    [HttpPost]
    public ActionResult Edit(int id, FormCollection collection)
    {
      Dinner dinner = dinnerrepository.GetDinner(id);
      if(TryUpdateModel(dinner))
      {
        dinnerrepository.Save();
        return RedirectToAction("Index");  
      }
      else
        return View(new DinnerFormViewModel(dinner));
    }

这是DinnerRepository里的代码

using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace Nerddinner.Models
{
  public class DinnerRepository
  {
    private NerdDinnerEntities entities = new NerdDinnerEntities();

    public IQueryable<Dinner> FindAllDinners()
    {
      return entities.Dinners;
    }

    public IQueryable<Dinner> FindUpcomingDinners()
    {
      return from dinner in entities.Dinners
          where dinner.EventDate > DateTime.Now
          orderby dinner.EventDate
          select dinner;
    }

    public Dinner GetDinner(int id)
    {
      return entities.Dinners.FirstOrDefault(d => d.DinnerID == id);
    }

    public void Add(Dinner dinner)
    {
      entities.Dinners.AddObject(dinner);
    }

    public void Delete(Dinner dinner)
    {
      foreach (var rsvp in dinner.RSVPs)
      {
        entities.RSVPs.DeleteObject(rsvp);
      }
      entities.Dinners.DeleteObject(dinner);
    }

    public void Save()
    {
      entities.SaveChanges();
    }
  }
}

这是DinnerFormViewModel里的代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace Nerddinner.Models
{
  public class DinnerFormViewModel
  {
    private static string[] _countries = new[]{
      "China",
      "Japan",
      "USA"};

    public Dinner Dinner { get; private set; }
    public SelectList Countries { get; private set; }

    public DinnerFormViewModel(Dinner dinner)
    {
      Dinner = dinner;
      Countries = new SelectList(_countries, dinner.Country);
    }
  }
}

这是Edit.aspx里代码


<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<Nerddinner.Models.DinnerFormViewModel>" %>

<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
	Edit:<%:Model.Dinner.Title %>
</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

  <h2>Edit a Dinner</h2>
  <%Html.RenderPartial("DinnerForm"); %>
</asp:Content>
里面使用了一个DinnerForm的partial view

代码如下：

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<Nerddinner.Models.DinnerFormViewModel>" %><br/><%:Html.ValidationSummary(false,"请更正所有错误")%><br/><%using (Html.BeginForm()){ %><br/><fieldset><br/><p><br/>    <%:Html.LabelFor(m=>m.Dinner.Title) %><br/>    <%:Html.TextBoxFor(m=>m.Dinner.Title) %><br/>    <%:Html.ValidationMessageFor(m=>m.Dinner.Title,"*") %><br/></p><br/><p><br/>    <%:Html.LabelFor(m=>m.Dinner.EventDate) %><br/>    <%:Html.TextBoxFor(m=>m.Dinner.EventDate) %><br/>    <%:Html.ValidationMessageFor(m=>m.Dinner.EventDate,"*") %><br/></p><br/><p><br/>    <%:Html.LabelFor(m=>m.Dinner.Description) %><br/>    <%:Html.TextAreaFor(m=>m.Dinner.Description) %><br/>    <%:Html.ValidationMessageFor(m=>m.Dinner.Description,"*") %><br/></p><br/><p><br/>    <%:Html.LabelFor(m=>m.Dinner.Address) %><br/>    <%:Html.TextBoxFor(m=>m.Dinner.Address) %><br/>    <%:Html.ValidationMessageFor(m=>m.Dinner.Address,"*") %><br/></p><br/><p><br/>    <%:Html.LabelFor(m=>m.Dinner) %><br/>    <%:Html.DropDownListFor(m=>m.Dinner.Country,Model.Countries) %><br/>    <%:Html.ValidationMessageFor(m=>m.Dinner.Title,"*") %><br/></p><br/><p><br/>    <%:Html.LabelFor(m=>m.Dinner.ContactPhone) %><br/>    <%:Html.TextBoxFor(m=>m.Dinner.ContactPhone) %><br/>    <%:Html.ValidationMessageFor(m=>m.Dinner.ContactPhone,"*") %><br/></p><br/><p><input type="submit" value="Save"/></p><br/></fieldset><br/><%} %>

有点长，希望专家有时间了帮我看看，我已经纠结两天了，实在搞不懂。。。<br/>

Answer 1

我至少没有看出明显的错误。这样你断点调试一下到Dinnner.GetDinner(int id)看看获得的Dinner是否是空，或者是否出现其它异常情况。

Answer 2

回去重新试了一下，好象加上那个partial view就不能更新了，如果不加的话是可以更新的，直接看实例还是有很多不理解的地方啊。

Answer 3

程序有误。

controller传递给view的是DinnerFormViewModel类，而TryUpdateModel的则是Dinner类，所以不能更新。