当navigational属性为null时，模型无效

Question

我是ASP mvc和实体框架的新手 我有一个由实体框架创建的模型

serialver

如您所见，public partial class Privilege { public Privilege() { this.Role_Privilege_Map = new HashSet<Role_Privilege_Map>(); } public int PrivilegeId { get; set; } [Required(ErrorMessage="*")] [Display(Name = "Privilege Name")] public string PrivilegeName { get; set; } [Required(ErrorMessage = "*")] public Nullable<int> ModuleId { get; set; } public virtual module module { get; set; } public virtual ICollection<Role_Privilege_Map> Role_Privilege_Map { get; set; } } 是一个导航属性。

我已将此模型绑定到视图

module

我有一个更新按钮，用于更新此模型，说明权限名称。现在我的行​​动

@for (var i = 0; i < Model.Count(); i++)
        {
            <tr>
                <td>
                    @Html.DisplayFor(modelItem => modelItem[i].PrivilegeName)
                    @Html.HiddenFor(modelItem => modelItem[i].PrivilegeId)
                    @Html.HiddenFor(modelItem => modelItem[i].PrivilegeName)
                </td>
                <td>
                    @Html.DisplayFor(modelItem => modelItem[i].module.ModuleName)
                    @Html.HiddenFor(modelItem => modelItem[i].ModuleId)
                    @Html.HiddenFor(modelItem => modelItem[i].module.ModuleName)
                    @Html.HiddenFor(modelItem => modelItem[i].module)
                </td>
                <td>
                    @Html.CheckBoxFor(modelItem => modelItem[i].Checked)
                    @Html.HiddenFor(modelItem => modelItem[i].Checked)
                </td>
                <td>
                    @Html.ActionLink("Edit", "OpenEditPrivilegeDialog", "RolePrivilegeMapping",
                        new { id = Model[i].PrivilegeId }, 
                        new { @class = "actionHyperLink edit_Privilege_Link" }) |
                    @Html.ActionLink("Delete", "DeletePrivilege","RolePrivilegeMapping",
                        new { id = Model[i].PrivilegeId }, 
                        new { @class = "actionHyperLink Delete_Privilege_Link" })
                </td>
            </tr>
        }

返回false。我放了一个断点，并且知道导航属性为null，这可能是模型无效的原因。我怎么能超越这个。正如您在代码中看到的，我添加了一个用于绑定导航属性的隐藏字段

为什么会这样？任何帮助将不胜感激

根据wiz kid提供的帖子ModelState.IsValid == false, why?

我知道那里出现了褐色异常

 public ActionResult UpdateRolePrivilege(IList<One_Track.Models.Privilege> updatedPrivilege)
        {


                if (ModelState.IsValid)
                {

                }
                else
                {
                    ViewBag.PrivilegeMessage = "Privileges updation Failed.";
                }
            }

            return PartialView("PrivilegePartial", sample.GetPrivilegeNames());
        }

所以我从视图中删除了该行

The parameter conversion from type 'System.String' to type 'sample.Models.module' failed because no type converter can convert between these types.
   at System.Web.Mvc.ValueProviderResult.ConvertSimpleType(CultureInfo culture, Object value, Type destinationType)
   at System.Web.Mvc.ValueProviderResult.UnwrapPossibleArrayType(CultureInfo culture, Object value, Type destinationType)
   at System.Web.Mvc.ValueProviderResult.ConvertTo(Type type, CultureInfo culture)
   at System.Web.Mvc.DefaultModelBinder.ConvertProviderResult(ModelStateDictionary modelState, String modelStateKey, ValueProviderResult valueProviderResult, Type destinationType)}

这解决了问题