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我是新來的Asp.net MVC和工作在一個簡單的博客應用程序（Asp.Net MVC5，EF6）學習。插入父表時插入在外鍵表中的新記錄
我在解決方案體系結構中使用存儲庫模式，並使用EF代碼首次遷移Ninject for DI。在客戶端，我使用jQuery Grid for Admin來管理帖子，類別和標籤。
- Blog.Model：Post.cs，Category.cs，Tags.cs
public class Post
{
[Required(ErrorMessage = "Id is required")]
public int Id { get; set; }
[Required(ErrorMessage = "Title is required")]
[StringLength(500, ErrorMessage = "Title cannot be more than 500 characters long")]
public string Title { get; set; }
[Required(ErrorMessage = "Short description is required")]
public string ShortDescription { get; set; }
[Required(ErrorMessage = "Description is required")]
public string Description { get; set; }
public bool Published { get; set; }
[Required(ErrorMessage = "PostedOn date is required")]
public DateTime PostedOn { get; set; }
public DateTime? ModifiedOn { get; set; }
[ForeignKey("Category")]
public virtual int CategoryId { get; set; }
public virtual Category Category { get; set; }
public virtual IList<Tag> Tags { get; set; }
}
public class Category
{
[Key]
public int CategoryId { get; set; }
[Required(ErrorMessage = "Category Name is required")]
[StringLength(500,ErrorMessage = "Category name length cannot exceed 500")]
public string Name { get; set; }
[Required(ErrorMessage = "Category Name is required")]
[StringLength(500, ErrorMessage = "Category name length cannot exceed 500")]
public string Description { get; set; }
[JsonIgnore]
public virtual IList<Post> Posts { get; set; }
}
public class Tag
{
public int Id { get; set; }
[Required(ErrorMessage = "Name is required")]
[StringLength(500, ErrorMessage = "Name length should not exceed 500 characters")]
public string Name { get; set; }
public string Description { get; set; }
[JsonIgnore]
public IList<Post> Posts { get; set; }
}
- Blog.Repository：BlogRepository，IBlogRepository，BlogContext
public interface IBlogRepository
{
int SavePost(Post post);
//Other methods...
}
public class BlogRepository : BlogContext, IBlogRepository
{
public BlogContext _db;
public BlogRepository(BlogContext db)
{
_db = db;
}
public int SavePost(Post post)
{
_db.Posts.Add(post);
_db.SaveChanges();
return post.Id;
}
//Other implementations...
}
public class BlogContext : DbContext, IDisposedTracker
{
public BlogContext() : base("BlogDbConnection") { }
public DbSet<Post> Posts { get; set; }
public DbSet<Tag> Tags { get; set; }
public DbSet<Category> Categories { get; set; }
public bool IsDisposed { get; set; }
protected override void Dispose(bool disposing)
{
IsDisposed = true;
base.Dispose(disposing);
}
- Blog.Web：AdminController.cs，NinjectWebCommon.cs
AdminController以Json格式發送/使用數據。
public class AdminController : Controller
{
private readonly IBlogRepository _blogRepository;
public AdminController(IBlogRepository blogRepository)
{
_blogRepository = blogRepository;
}
//POST: /Admin/CreatePost
[HttpPost, ValidateInput(false)]
public ContentResult CreatePost([ModelBinder(typeof(PostModelBinder))] Post model)
{
string json;
ModelState.Clear();
if (TryValidateModel(model))
{
var id = _blogRepository.SavePost(model);
json = JsonConvert.SerializeObject(
new
{
id = id,
success = true,
message = "Post saved successfully."
});
}
else
{
json = JsonConvert.SerializeObject(
new
{
id = 0,
success = false,
message = "Post not saved."
});
}
return Content(json, "application/json");
}
}
public static class NinjectWebCommon
{
private static void RegisterServices(IKernel kernel)
{
kernel.Bind<BlogContext>().ToSelf(); //This isn't helping either
kernel.Bind<IBlogRepository>().To<BlogRepository>();
}
}
我使用自定義模型綁定，因爲我得到驗證異常，而郵政儲蓄自分類的列表，並從電網獲得的標籤不映射到應用程序中的模型實際的對象。因此，在自定義模型綁定中，我使用從網格接收的實際對象填充Post對象。這個Post對象被髮送給使用DbContext和Repository保存到數據庫的控制器。
public class PostModelBinder : DefaultModelBinder
{
public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
var post = (Post)base.BindModel(controllerContext, bindingContext);
**var blogRepository = new BlogRepository(new BlogContext());**//I think here I need to inject the dependency for BlogContext, but don't know how to do that.
if (post.Category != null)
{
post.Category = blogRepository._db.Categories.AsNoTracking().Single(c => c.CategoryId == post.Category.CategoryId);
}
var tags = bindingContext.ValueProvider.GetValue("Tags").AttemptedValue.Split(',');
if (tags.Length > 0)
{
post.Tags = new List<Tag>();
foreach (var tag in tags)
{
var id = int.Parse(tag.Trim());
post.Tags.Add(blogRepository._db.Tags.AsNoTracking().Single(t => t.Id == id));
}
}
if (bindingContext.ValueProvider.GetValue("oper").AttemptedValue.Equals("edit"))
post.ModifiedOn = DateTime.UtcNow;
else
post.PostedOn = DateTime.UtcNow;
return post;
}
}
問題：當後保存，數據上下文插入其各自的表中分類和標籤的新行。新創建的帖子引用了外鍵列下的新類別（Id：22）。
帖子：
類別：
標籤：
我想這樣做的原因是，當恩tity被保存，它被附加到一個不同的ObjectContext，我需要將它附加到當前的上下文，但不知道如何？我發現類似的question asked before，但沒有一個公認的答案。任何幫助將不勝感激。