【发布时间】：2010-08-25 16:15:28
【问题描述】：
我在实现 ViewModel 类时遇到问题，该类充当 L2SQL 生成的名为 "User" 的模型类的包装类。简而言之，当我必须针对 L2SQL 模型进行验证时，我有两个实例。一种是用户第一次注册，另一种是用户登录并仅编辑其部分帐户数据。
最初的“问题”是在尝试从仅显示少数几个（例如名字、姓氏、电子邮件）的视图中针对原始 L2SQL 模型仅编辑和验证一些帐户详细信息时，运行验证时，缺少的（例如密码）会突然出现。密码设置将有自己的视图。
我在 StackOverflow 上被告知，添加一个包装 ViewModel 类将是最好的解决方案。所以我做到了，实现如下：
ViewModel 代码：
[Bind]
public class AccountEdit
{
public User UserAccount { get; set; }
[Required(ErrorMessage = "First name required"), StringLength(20, MinimumLength = 3, ErrorMessage = "Must be between 3 and 20 characters")]
public string FirstName { get { return UserAccount.FirstName; } set { UserAccount.FirstName = value; } }
[Required(ErrorMessage = "Last name required"), StringLength(20, MinimumLength = 3, ErrorMessage = "Must be between 3 and 20 characters")]
public string LastName { get { return UserAccount.LastName; } set { UserAccount.LastName = value; } }
[Required(ErrorMessage = "Email address required"), RegularExpression("^[a-z0-9_\\+-]+(\\.[a-z0-9_\\+-]+)*@[a-z0-9-]+(\\.[a-z0-9-]+)*\\.([a-z]{2,4})$", ErrorMessage = "Must be a valid email address")]
public string Email { get { return UserAccount.Email; } set { UserAccount.Email = value; } }
}
控制器代码：
//
// GET /User/Account
public ActionResult Account()
{
string cookieUser = User.Identity.Name;
User user = userRepository.GetUserByEmail(cookieUser);
return View(user);
}
// POST /User/Account
[HttpPost]
public ActionResult Account(AccountEdit model)
{
if (ModelState.IsValid)
{
model.LastUpdated = DateTime.Now;
userRepository.Save();
}
return View(model);
}
查看代码：
<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/User.Master" Inherits="System.Web.Mvc.ViewPage<Digitalent.Models.User>" %>
<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
Account settings
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<% using (Html.BeginForm()) {%>
<%= Html.ValidationSummary("Oops! Please correct the errors and try again!") %>
<p>
<label for="FirstName">First name:</label>
<%: Html.TextBoxFor(model => model.FirstName, new { @class = "textfield" })%>
<%: Html.ValidationMessageFor(model => model.FirstName) %>
</p>
<p>
<label for="LastName">Last name:</label>
<%: Html.TextBoxFor(model => model.LastName, new { @class = "textfield" })%>
<%: Html.ValidationMessageFor(model => model.LastName) %>
</p>
<p>
<label for="Email">Email address:</label>
<%: Html.TextBoxFor(model => model.Email, new { @class = "textfield" })%>
<%: Html.ValidationMessageFor(model => model.Email) %>
</p>
<p>
Email newsletter: <%= Html.CheckBoxFor(model => model.EmailNewsletter) %>
<label for="EmailNewsletter">Keep me posted with latest Digitalent happenings.</label>
</p>
<p>
<input type="submit" value="Save changes" class="button" />
</p>
<p><a href="/talent/password">Change your password settings</a></p>
<% } %>
但现在当我尝试运行应用程序时，我在运行验证时遇到错误：
'对象引用未设置为对象的实例。'
在我的 ViewModel 的下面一行：
'public string FirstName { get { return UserAccount.FirstName; } 设置 { UserAccount.FirstName = 值； } }'
我哪里出错了，或者其他人可以告诉我更好的推荐方法，因为我是新手。请帮忙！
【问题讨论】：
标签： asp.net-mvc linq-to-sql validation viewmodel