我是MVC的初学者,试图创建一个页面...我的数据库中有三个表...我正在使用Entity Framework DB的第一种方法,并将这三个表创建为“模型”文件夹下的类...我还创建了一个名为“ AllClasses”的新类,并在该新类中定义了这三个类中的每一个...
我正在尝试从“ tblCharacter”表“ CharacterImageURL”列中获取3张图片...
当我运行代码“ return View(myclass)”时,出现错误=> System.NullReferenceException:System.Web.Mvc.WebViewPage.Model.get返回null ...
问题是return View(myclass);
返回NULL ...所以问题出在我的控制器上,我想...
我知道没有适用于我的解决方案的类似问题...
这是我的控制器部分:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using StarWars.Models;
namespace StarWars.Controllers
{
public class HomeController : Controller
{
StarWarsFunClubDBEntities myobject = new StarWarsFunClubDBEntities();
public ActionResult Index()
{
return View();
}
public ActionResult SWHome()
{
var myclass = new AllClasses();
myclass.Avatars = myobject.tblAvatars.ToList();
myclass.Characters = myobject.tblCharacters.ToList();
myclass.Comments = myobject.tblComments.ToList();
return View(myclass);
}
}
}
这是我的主页SWHome.cshtml
@model StarWars.Models.AllClasses
@{
Layout = null;
}
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>SWHome</title>
<link rel="stylesheet" type="text/css" href="~/Content/css.css" />
</head>
<body>
<div class="box">
<div class="header">
<div class="logo"> <img src="~/images/Star_Wars_Logo.png" alt="Alternate Text" /> </div>
<div class="sitename"><h4>Star Wars Fun Club</h4></div>
</div>
<div class="question"><h5>What do you think about the new characters of Star Wars: The Force Awakens(2015)?</h5></div>
<div class="photo">
<div class="innerphoto">
@foreach (var item in Model.Characters)
{
<img src="@item.CharacterImageURL" alt="" />
}
</div>
</div>
<div class="comment"></div>
<div class="addcomment"></div>
<div class="footer"></div>
</div>
</body>
</html>
这些是我通过EF DB First帮助自动生成的类
namespace StarWars.Models
{
using System;
using System.Collections.Generic;
public partial class tblAvatar
{
public int AvatarID { get; set; }
public string AvatarName { get; set; }
public string AvatarImageURL { get; set; }
}
}
namespace StarWars.Models
{
using System;
using System.Collections.Generic;
public partial class tblComment
{
public int CommentID { get; set; }
public string Expression { get; set; }
public System.DateTime DateTime { get; set; }
public int AvatarID { get; set; }
}
}
namespace StarWars.Models
{
using System;
using System.Collections.Generic;
public partial class tblCharacter
{
public int CharacterID { get; set; }
public string CharacterName { get; set; }
public string CharacterImageURL { get; set; }
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using StarWars.Models;
using StarWars.Controllers;
using System.Data.Entity;
namespace StarWars.Models
{
public class AllClasses
{
public IEnumerable<tblAvatar> Avatars { get; set; }
public IEnumerable<tblCharacter> Characters { get; set; }
public IEnumerable<tblComment> Comments { get; set; }
}
}
答案 0 :(得分:0)
您使用方法SWHome()
返回了对象AllClasses
,但是您的视图除外了List<AllClasses>
。
也许这是为您提供的解决方案:
@model StarWars.Models.AllClasses
代替
@model List<StarWars.Models.AllClasses>
以及图片的解决方案:
@foreach (var Character in Model.Characters)
{
@if (Character.CharacterImageURL != null)
{
<img src="@Character.CharacterImageURL" alt="" />
}
}
或没有空检查:
@foreach (var Character in Model.Characters)
{
<img src="@Character.CharacterImageURL" alt="" />
}
答案 1 :(得分:0)
您在视图中有List<StarWars.Models.AllClasses>
,但是您正在从方法AllClasses
返回SWHome
。
根据您的情况,您需要使用@model StarWars.Models.AllClasses
删除视图中的foreach
循环。并直接访问该属性。 Model.Characters