我发现了很多关于此的文章,但我仍然不知道到底如何做到这一点。我正在尝试创建自己的博客引擎,我有用于创建文章的视图(我首先使用 EF 和代码),现在我必须填写应添加文章的类别数量,但我想将其更改为下拉列表,名称为类别。我的模型看起来是这样的:
public class Article
{
public int ArticleID { get; set; }
[Required]
public string Title { get; set; }
[Required]
public int CategoryID { get; set; }
public DateTime Date { get; set; }
[Required()]
[DataType(DataType.MultilineText)]
[AllowHtml]
public string Text { get; set; }
public virtual Category Category { get; set; }
public IEnumerable<SelectListItem> Categories { get; set; }
public virtual ICollection<Comment> Comments { get; set; }
}
public class Category
{
public int CategoryID { get; set; }
[Required]
public string Name { get; set; }
public virtual ICollection<Article> Articles { get; set; }
}
我知道我必须使用 Enum (或者我认为),但我不太确定如何使用。我不知道我找到的哪个教程最适合我。
Edit:
感谢您的回答,但我发现了其他东西。我正在尝试这个:
这是我的模型:
public class Article
{
[Key]
public int ArticleID { get; set; }
[Display(Name = "Title")]
[StringLength(30, MinimumLength = 5)]
[Required]
public string Title { get; set; }
public DateTime Date { get; set; }
public int CategoryID { get; set; }
[Required()]
[DataType(DataType.MultilineText)]
[AllowHtml]
public string Text { get; set; }
public Category Category { get; set; }
public virtual ICollection<Comment> Comments { get; set; }
public IEnumerable<Category> Categories { get; set; }
}
public class Category
{
[Key]
public int CategoryId { get; set; }
[Required]
public string CategoryName { get; set; }
public virtual ICollection<Article> Articles { get; set; }
}
这是我创建文章的控制器:
public ActionResult Vytvorit()
{
IEnumerable<Category> categories = GetCaregories();
var view = View(new Article() { Categories = categories });
view.TempData.Add("Action", "Create");
return view;
}
private static IEnumerable<Category> GetCaregories()
{
IEnumerable<Category> categories;
using (BlogDBContext context = new BlogDBContext())
{
categories = (from one in context.Categories
orderby one.CategoryName
select one).ToList();
}
return categories;
}
private Category GetCategory(int categoryID)
{
return db.Categories.Find(categoryID);
}
//
// POST: /Clanky/Vytvorit
[HttpPost]
public ActionResult Vytvorit(Article newArticle)
{
try
{
if (newArticle.CategoryID > 0)
{
newArticle.Category = GetCategory(newArticle.CategoryID);
}
if (TryValidateModel(newArticle))
{
db.Articles.Add(newArticle);
db.SaveChanges();
return RedirectToAction("Index");
}
else
{
newArticle.Categories = GetCaregories();
var view = View(newArticle);
view.TempData.Add("Action", "Create");
return view;
}
}
catch
{
return View();
}
}
这是我观点的一部分:
@Html.DropDownListFor(model => model.CategoryID, new SelectList(Model.Categories,"CategoryID","CategoryName"))
@Html.ValidationMessageFor(model => model.CategoryID)
我遇到 NullReferenceException 问题,但我不知道为什么。我可以这样做吗?对我来说看起来很容易。