Question

我设法注册了一个applicationuser，现在我想发一个HTTP GET请求，在View中显示当前登录用户的帐户详细信息。

但是，当我运行应用程序并转到“MyPages”视图时，我得到一个异常，说嵌套的CustomerViewModel为null。我完全不知道为什么，但出于某种原因它是。

这是HomeController.cs中的actionresult

public ActionResult MyPages()
{
    string userId = User.Identity.GetUserId();
    var currentUser = _userRepository.GetById(userId);
    var customer = _customerRepository.GetById(currentUser.Customer.Id);

    var userViewModel = new UserViewModel();
    userViewModel.Id = currentUser.Id;
    userViewModel.UserName = currentUser.UserName;

    //This is where the exception occurs. Apperantly CustomerViewModel is null                      
    userViewModel.CustomerViewModel.Id = customer.Id;
    userViewModel.CustomerViewModel.FirstName = customer.FirstName;
    userViewModel.CustomerViewModel.LastName = customer.LastName;
    userViewModel.CustomerViewModel.Email = customer.Email;           

    return View(userViewModel);
}

这是UserViewModel

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Security;
using Microsoft.AspNet.Identity.EntityFramework;

namespace GUI.Models
{
    public class UserViewModel
    {
        public virtual string Id { get; set; }
        public virtual string UserName { get; set; }
        public virtual string PasswordHash { get; set; }
        public virtual string SecurityStamp { get; set; }

        public virtual ICollection<IdentityUserRole> Roles { get; set; }
        public virtual ICollection<IdentityUserClaim> Claims { get; set; }
        public virtual ICollection<IdentityUserLogin> Logins { get; set;  }

        public CustomerViewModel CustomerViewModel { get; set; }
    }
}

这是CustomerViewModel：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using ClassLibrary.Entities;

namespace GUI.Models
{
    public class CustomerViewModel
    {
        public Guid Id { get; set; }

        [Required]
        [Display(Name = "First Name")]
        public string FirstName { get; set; }

        [Required]
        [Display(Name = "Last Name")]
        public string LastName { get; set; }

        [Display(Name = "Email Adress")]
        [Required(ErrorMessage = "Email address is required")]
        [EmailAddress(ErrorMessage = "Invalid Email Address")]
        public string Email { get; set; }

        public List<InvoiceViewModel> InvoiceViewModels { get; set; }
        public List<AddressViewModel> AdressViewModels { get; set; }

        public AddressViewModel AdressViewModel { get; set; }

        public virtual ICollection<Invoice> Invoice { get; set; }
        public virtual ICollection<Adress> Adress { get; set; }
    }
}

这里似乎有什么问题？

Answer 1

我可能会在您的代码中遗漏某些内容，但它似乎不会为CustomerViewModel实例化新的userViewModel.CustomerViewModel。

您可以节省一些麻烦，让UserViewModel为您创建一个新实例：

public class UserViewModel
{
    public UserViewModel()
    {
        CustomerViewModel = new CustomerViewModel();
    }

    public CustomerViewModel CustomerViewModel { get; set; }
}

Answer 2

请使用以下代码

替换您的UserViewModel Model类

公共类UserViewModel

{

    public virtual string Id { get; set; }
    public virtual string UserName { get; set; }
    public virtual string PasswordHash { get; set; }
    public virtual string SecurityStamp { get; set; }
    public UserViewModel()
    {
        CustomerViewModel = new CustomerViewModel();
    }

    public CustomerViewModel CustomerViewModel { get; set; }
}

为什么我的嵌套CustomerViewModel为null？

2 个答案: