我坐着＆＃39;我在学校的最后一个项目，但在完成它时遇到了一些麻烦。
首先，我在以下tutorial的帮助下创建了一个Webstore。这是一个基于MVC 3的教程，但是我用它来制作最新版本。
之后我想根据相同的原则制作某种博客文章数据库，这就是我遇到麻烦的地方。
我已将该文章作为模型：
public class Article
{
[Key]
public int ArticleId { get; set; }
public int SubjectId { get; set; }
public string Title { get; set; }
public string MainText { get; set; }
public string PictureURL { get; set; }
public ArticleSubject ArticleSubject { get; set; }
}
之后我创建了ArticleSubject：
public class ArticleSubject
{
[Key]
public int SubjectId { get; set; }
public string Title { get; set; }
public string Description { get; set; }
public List<Article> Articles { get; set; }
}
然后我创建了NewsEntities DbContext：
public class NewsEntities : DbContext
{
public DbSet<Article> Articles { get; set; }
public DbSet<ArticleSubject> ArticleSubjects { get; set; }
}
最后，我填写了一个＆＃34; NewsData＆＃34;类：
public class NewsData : DropCreateDatabaseIfModelChanges<NewsEntities>
{
protected override void Seed(NewsEntities context)
{
var articleSubjects = new List<ArticleSubject>
{
new ArticleSubject { Title = "Almindelige Nyheder" },
new ArticleSubject { Title = "Arrangementer" },
new ArticleSubject { Title = "Udstillinger" }
};
}
}
然后我使用Entity Framework创建了一个NewsManagerController。当我运行我的应用程序，并将创建一个新文章时，主题下拉列表为空。我一直在寻找一个没有运气的解决方案。
我希望你能帮助我！您可以随意索取更多代码段或信息。
谢谢！
// refnedergaard
编辑：
控制器：
public class NewsManagerController : Controller
{
private NewsEntities db = new NewsEntities();
// GET: NewsManager
public ActionResult Index()
{
var articles = db.Articles.Include(a => a.ArticleSubject);
return View(articles.ToList());
}
// GET: NewsManager/Details/5
public ActionResult Details(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Article article = db.Articles.Find(id);
if (article == null)
{
return HttpNotFound();
}
return View(article);
}
// GET: NewsManager/Create
public ActionResult Create()
{
ViewBag.SubjectId = new SelectList(db.ArticleSubjects, "SubjectId", "Title");
return View();
}
// POST: NewsManager/Create
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "ArticleId,SubjectId,Title,MainText,PictureURL")] Article article)
{
if (ModelState.IsValid)
{
db.Articles.Add(article);
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.SubjectId = new SelectList(db.ArticleSubjects, "SubjectId", "Title", article.SubjectId);
return View(article);
}
// GET: NewsManager/Edit/5
public ActionResult Edit(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Article article = db.Articles.Find(id);
if (article == null)
{
return HttpNotFound();
}
ViewBag.SubjectId = new SelectList(db.ArticleSubjects, "SubjectId", "Title", article.SubjectId);
return View(article);
}
// POST: NewsManager/Edit/5
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see http://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include = "ArticleId,SubjectId,Title,MainText,PictureURL")] Article article)
{
if (ModelState.IsValid)
{
db.Entry(article).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.SubjectId = new SelectList(db.ArticleSubjects, "SubjectId", "Title", article.SubjectId);
return View(article);
}
// GET: NewsManager/Delete/5
public ActionResult Delete(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Article article = db.Articles.Find(id);
if (article == null)
{
return HttpNotFound();
}
return View(article);
}
// POST: NewsManager/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public ActionResult DeleteConfirmed(int id)
{
Article article = db.Articles.Find(id);
db.Articles.Remove(article);
db.SaveChanges();
return RedirectToAction("Index");
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
db.Dispose();
}
base.Dispose(disposing);
}
}
创建视图：
@model boerglumklosterdk.Models.Article
@{
ViewBag.Title = "Create";
Layout = "~/Views/Shared/_Layout.cshtml";
}
<h2>Create</h2>
@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
<div class="form-horizontal">
<h4>Article</h4>
<hr />
@Html.ValidationSummary(true, "", new { @class = "text-danger" })
<div class="form-group">
@Html.LabelFor(model => model.SubjectId, "SubjectId", htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("SubjectId", null, htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.SubjectId, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.Title, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.Title, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.Title, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.MainText, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.MainText, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.MainText, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.PictureURL, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.PictureURL, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.PictureURL, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
</div>
}
<div>
@Html.ActionLink("Back to List", "Index")
</div>
答案 0 :(得分：1)
您创建了要添加到上下文中的主题列表，但您从未将种子数据保存到上下文中。你可以尝试：
public class NewsData : DropCreateDatabaseIfModelChanges<NewsEntities>
{
protected override void Seed(NewsEntities context)
{
context.ArticleSubjects.AddOrUpdate(
p => p.Title,
new ArticleSubject { Title = "Almindelige Nyheder" },
new ArticleSubject { Title = "Arrangementer" },
new ArticleSubject { Title = "Udstillinger" }
);
}
}
答案 1 :(得分：0)
我认为您的问题是因为您没有将ArticleSubject列表保存到您的数据库中。您需要先在ArticleSubjects DbSet中添加它们，然后调用上下文的SaveChanges方法：
context.ArticleSubjects.AddRange(articleSubjects);
context.SaveChanges();
现在，如果您使用Migration，则在模型更改的情况下，您不会丢弃数据库，因此您可能希望使用@Sam变体来避免重复。
此外，为了执行自定义初始值设定项，您必须通过Initializer属性设置数据库Database：
public class NewsEntities : DbContext
{
public DbSet<Article> Articles { get; set; }
public DbSet<ArticleSubject> ArticleSubjects { get; set; }
public NewsEntities()
{
Database.SetInitializer(new NewsData());
}
}