取一个与后所有评论有关该职位在Asp.net mvc4沿 [英] Fetching a single post along with all comments relating to that post in Asp.net mvc4
问题描述
大家好，
我psently面临的一个问题$ P $与使用id参数的查询字符串从数据库中获取一个职位，也找回属于该职位所有评论的查询。到目前为止，我知道，我希望有一个单一的职位，因此我认为不会包含IEnumerable接口，因为我的查询我使用。单（）。但是，由于我是从数据库中获取的评论列表，不只是一个评论我知道这将是IEnumerable的。我的问题是如何将两者结合起来的接口，这样我可以显示单一的职位和属于它的所有意见。
公共类ReadPostsVM
{
公共字符串PostTitle {搞定;组; } 公共字符串PostContent {搞定;组; } 公共字符串PostAuthor {搞定;组; } 公众的DateTime踵{搞定;组; } 公共字符串评论{搞定;组; } 公共字符串CommentAuthor {搞定;组; } 公众的DateTime CommentDate {搞定;组; }
}
这是我试图在控制器
公众的ActionResult ReadPost（INT ID）
{
VAR的查询=从db.Posts.Where P（P =＆GT; p.PostId == ID）
从C在db.Replies.Where（C =＆GT; c.PostId == ID）
走进你的db.UserProfiles
在p.AuthorId等于u.UserId
其中，p.PostId == ID
选择新ReadPostsVM（）
{
PostTitle = p.PostTitle，
PostContent = p.PostContent，
踵= p.DateCreated，
PostAuthor = u.UserName，
注释= c.Reply1，
CommentAuthor = u.UserName，
CommentDate = c.ReplyDate
}; VAR查询从db.Posts P =
走进你的db.UserProfiles
在p.AuthorId等于u.UserId
其中，p.PostId == ID
选择新ReadPostsVM（）
{
PostTitle = p.PostTitle，
PostContent = p.PostContent，
踵= p.DateCreated，
PostAuthor = u.UserName， }; 返回查看（query.Single（））;
}
然而在视图中我有
@model IEnumerable的＆LT; Blogger.ViewModels.ReadPostsVM＆GT;
和这给了我一个错误foreach循环话说
序列中不包含任何元素
我觉得我有另一种选择是只此获取以下
公众的ActionResult ReadPost（INT ID）
{ VAR查询从db.Posts P =
走进你的db.UserProfiles
在p.AuthorId等于u.UserId
其中，p.PostId == ID
选择新ReadPostsVM（）
{
PostTitle = p.PostTitle，
PostContent = p.PostContent，
踵= p.DateCreated，
PostAuthor = u.UserName， }; 返回查看（query.Single（））;
}
要获得使用只返回一个职位，一个职位，也许我就可以使用一个局部视图来显示评论。
@model Blogger.ViewModels.ReadPostsVM
请帮我我怎么能达到这个目的。如果我使用的局部视图我怎么能作出这样的局部视图，以基于URL的参数提取评论，因为我将不得不调用与id参数的行动，但我没有任何链接指向该网页，还我不认为它将使感这样。我希望我的问题是有道理的？请帮助！
要显示的帖子实体，我添加了Posts.cs类和Replies.cs类以下
的意见实体之间的关系 公共部分类帖子
{
公共邮政（）
{
this.Replies =新的HashSet＆LT;回覆与GT;（）;
} 公众诠释{帖子ID获取;组; }
公共字符串PostTitle {搞定;组; }
公共字符串PostContent {搞定;组; }
公众诠释AUTHORID {搞定;组; }
公众诠释的CategoryId {搞定;组; }
公众的System.DateTime dateCreated会获得{;组; } 公共虚拟分类分类{搞定;组; }
公共虚拟用户配置用户配置{搞定;组; }
公共虚拟的ICollection＆LT;回覆与GT;回复{搞定;组; }
} 公共部分类回复
{
公众诠释ReplyId {搞定;组; }
公共字符串REPLY1 {搞定;组; }
公众的System.DateTime ReplyDate {搞定;组; }
公众诠释AUTHORID {搞定;组; }
公众诠释{帖子ID获取;组; }
公众诠释的CategoryId {搞定;组; } 公共虚拟分类分类{搞定;组; }
公共虚拟文章张贴{搞定;组; }
公共虚拟用户配置用户配置{搞定;组; }
}
您需要更改您的视图模型，使后视图模型包含注释集合
查看模型
公共类CommentVM
{
公共字符串评论{搞定;组; }
公共字符串CommentAuthor {搞定;组; }
公众的DateTime CommentDate {搞定;组; }
}公共类PostVM
{
公共字符串PostTitle {搞定;组; }
公共字符串PostContent {搞定;组; }
公共字符串PostAuthor {搞定;组; }
公众的DateTime踵{搞定;组; }
清单＆LT; CommentVM＆GT;评论{搞定;组; }
}
控制器（我会向你要隐蔽LINQ to SQL的离开吧）
公众的ActionResult ReadPost（INT ID）
{
后后= db.Posts.Find（ID）;
PostVM模式=新PostVM（）
{
PostTitle = post.PostTitle，
PostContent = post.PostContent，
PostAuthor = post.UserProfile.UserName，
踵= post.DateCreated，
评论= post.Replies.Select（R = GT;新CommentVM（）
{
注释= r.Reply1，
CommentAuthor = r.UserProfile.UserName，
CommentDate = r.ReplyDate
}）
};
返回查看（模型）;
}
查看
@model PostVM
...
@DisplayFor（M =＆GT; m.PostTitle）
...
@DisplayFor（M =＆GT; m.PostDate）@foreach（在Model.Comments VAR评论）
{
@DisplayFor（comment.Comment）
...
@DisplayFor（comment.CommentDate）
}
Hello Everyone, I am facing a problem presently with a query that uses the id parameter in the query string to fetch a single post from the database and also retrieve all comments that belong to the posts. So far i know that i want a single post hence my view will not contain the IEnumerable interface because in my query i use .single(). However since i'm fetching a list of comments from the database and not just one comment i know that will be IEnumerable. My problem is how to combine both interfaces so that i can display that single post and all comments that belong to it .
public class ReadPostsVM
{
public string PostTitle { get; set; }
public string PostContent { get; set; }
public string PostAuthor { get; set; }
public DateTime PostDate { get; set; }
public string Comment { get; set; }
public string CommentAuthor { get; set; }
public DateTime CommentDate { get; set; }
}
This is what i tried in the controller
public ActionResult ReadPost(int id)
{
var query = from p in db.Posts.Where(p => p.PostId == id)
from c in db.Replies.Where(c => c.PostId == id)
join u in db.UserProfiles
on p.AuthorId equals u.UserId
where p.PostId == id
select new ReadPostsVM()
{
PostTitle = p.PostTitle,
PostContent = p.PostContent,
PostDate = p.DateCreated,
PostAuthor = u.UserName,
Comment = c.Reply1,
CommentAuthor = u.UserName,
CommentDate = c.ReplyDate
};
var query = from p in db.Posts
join u in db.UserProfiles
on p.AuthorId equals u.UserId
where p.PostId == id
select new ReadPostsVM()
{
PostTitle = p.PostTitle,
PostContent = p.PostContent,
PostDate = p.DateCreated,
PostAuthor = u.UserName,
};
return View(query.Single());
}
However in the view i have
@model IEnumerable<Blogger.ViewModels.ReadPostsVM>
and a foreach loop which gave me an error saying
Sequence does not contain any element
Another option i think i have is to fetch just this below
public ActionResult ReadPost(int id)
{
var query = from p in db.Posts
join u in db.UserProfiles
on p.AuthorId equals u.UserId
where p.PostId == id
select new ReadPostsVM()
{
PostTitle = p.PostTitle,
PostContent = p.PostContent,
PostDate = p.DateCreated,
PostAuthor = u.UserName,
};
return View(query.Single());
}
to get that single post using to return just a single post and maybe i can then use a Partial view to display the comments.
@model Blogger.ViewModels.ReadPostsVM
Please help me out how can I achieve this aim. If i am to use a partial view how can i make that partial view to fetch comments based on the parameter in the url since i will have to invoke an action with an id parameter but i dont have any link pointing to that page and also i dont think it would make sense like that. I hope my question makes sense? Please help!
To show the relationship between the Posts entity and the comments entity i have added the Posts.cs class and Replies.cs class below
public partial class Post
{
public Post()
{
this.Replies = new HashSet<Reply>();
}
public int PostId { get; set; }
public string PostTitle { get; set; }
public string PostContent { get; set; }
public int AuthorId { get; set; }
public int CategoryId { get; set; }
public System.DateTime DateCreated { get; set; }
public virtual Category Category { get; set; }
public virtual UserProfile UserProfile { get; set; }
public virtual ICollection<Reply> Replies { get; set; }
}
public partial class Reply
{
public int ReplyId { get; set; }
public string Reply1 { get; set; }
public System.DateTime ReplyDate { get; set; }
public int AuthorId { get; set; }
public int PostId { get; set; }
public int CategoryId { get; set; }
public virtual Category Category { get; set; }
public virtual Post Post { get; set; }
public virtual UserProfile UserProfile { get; set; }
}
You need to change your view models so that the Post view model contains a collection of Comments
View models
public class CommentVM
{
public string Comment { get; set; }
public string CommentAuthor { get; set; }
public DateTime CommentDate { get; set; }
}
public class PostVM
{
public string PostTitle { get; set; }
public string PostContent { get; set; }
public string PostAuthor { get; set; }
public DateTime PostDate { get; set; }
List<CommentVM> Comments { get; set; }
}
Controller (I'll leave it to you covert to LINQ To SQL)
public ActionResult ReadPost(int id)
{
Post post = db.Posts.Find(id);
PostVM model = new PostVM()
{
PostTitle = post.PostTitle,
PostContent = post.PostContent,
PostAuthor = post.UserProfile.UserName,
PostDate = post.DateCreated,
Comments = post.Replies.Select(r => new CommentVM()
{
Comment = r.Reply1,
CommentAuthor = r.UserProfile.UserName,
CommentDate = r.ReplyDate
})
};
return View(model);
}
View
@model PostVM
...
@DisplayFor(m => m.PostTitle)
...
@DisplayFor(m => m.PostDate )
@foreach(var comment in Model.Comments)
{
@DisplayFor(comment.Comment)
...
@DisplayFor(comment.CommentDate)
}
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