Add comment - two model in one view - asp.net-mvc

Question

I would like to add two model in one view: CommentVM and BlogVM.
CommentVM - comments,
BlogVM - postDetails.
I try to add comment via ajax to my databse and than pass my two model in to view. But when I try to display my page I received error that my object is null (commentVM)
below code my controller
Any sugestion what I am doing wrong?
Thank for your help!
// GET: Admin/Blog/kategoria/{name}/post/id
[ActionName("post")]
public ActionResult PostDetails(int id)
{
//Declare BlogVM
BlogVM model;
CommentVM model2;
int id2;
using (Db db = new Db())
{
//Get the page
BlogDTO dto = db.Blog.Find(id);
//Confirm page exist
if (dto == null)
{
return Content("Taka strona nie istnieje!");
}
//Init BlogVM
model = new BlogVM(dto);
id2 = dto.Id;
// CommentDTO dto2 = db.Comments.Find(x => x.PostId == id2);
model2 = new CommentVM();
}
var finalItem = new DetailsComment
{
Blog = model,
Comment = model2
};
return View("PostDetails", finalItem);
}
code my models:
public class CommentVM
{
public CommentVM()
{
}
public CommentVM(CommentDTO row)
{
Id = row.Id;
Name = row.Name;
Body = row.Body;
PostId = row.PostId;
CreatedAt = row.CreatedAt;
}
public int Id { get; set; }
[Required]
[StringLength(50, MinimumLength = 3)]
public string Name { get; set; }
[Required]
[StringLength(50, MinimumLength = 3)]
public string Body { get; set; }
public int PostId { get; set; }
public DateTime CreatedAt { get; set; }
//public IEnumerable<CommentVM> CommentDetails { get; set; }
}
public class BlogVM
{
public BlogVM()
{
}
public BlogVM(BlogDTO row)
{
Id = row.Id;
Title = row.Title;
Slug = row.Slug;
Body = row.Body;
CategoryName = row.CategoryName;
CategoryId = row.CategoryId;
CreatedAt = row.CreatedAt;
Sorting = row.Sorting;
HasSidebar = row.HasSidebar;
}
public int Id { get; set; }
[Required]
[StringLength(50, MinimumLength = 3)]
public string Title { get; set; }
public string Slug { get; set; }
[Required]
[StringLength(int.MaxValue, MinimumLength = 3)]
[AllowHtml]
public string Body { get; set; }
public string CategoryName { get; set; }
[Required]
public int CategoryId { get; set; }
public DateTime CreatedAt { get; set; }
public int Sorting { get; set; }
public bool HasSidebar { get; set; }
public IEnumerable<SelectListItem> Categories { get; set; }
}
public class DetailsComment
{
public BlogVM Blog { get; set; }
public CommentVM Comment { get; set; }
public IEnumerable<CommentVM> CommentDetails { get; set; }
}
In my view
#foreach (var item in Model.CommentDetails)
{
<tr>
<td>
<div class="ajaxdivtd"></div>
#Html.DisplayFor(modelItem => item.Name)
</td>
<td>
#Html.DisplayFor(modelItem => item.Body)
</td>
<td>
#Html.DisplayFor(modelItem => item.CreatedAt)
</td>
</tr>
}

Answer 1

If, according to your comments, you have multiple comments per post, then here's what you need to do:
//Declare BlogVM
BlogVM model;
CommentVM model2; //you can probably get rid of this variable since you want multiple comments per post, rather than a single one, but that's up to you
List<CommentVM> commentsModel; //new List object to hold the multiple comments for the post
and:
id2 = dto.Id;
var dto2 = db.Comments.Find(x => x.PostId == id2);
//Convert dto2 from an list/enumerable of CommentDTO to a List<CommentVM>, perhaps via AutoMapper (or other such utility), or even manually via a foreach
commentsModel = YourConversionMethod(dto2);
finally:
var finalItem = new DetailsComment
{
Blog = model,
Comment = model2,
CommentDetails = commentsModel
};