How Do I Count Navigation Properties with Specific Values?

PostAlmostAnything 1

I have a couple queries for counting everything with specific integer value. The first one works, but the second fails. The one that works is:

int paarisgold = Posts.Where((Posts p) => p.Cap == 3).Count();
if(paarisgold > 0)
{
Capnoindex = true;
}

The one that fails is:

int paarisgoldcomment = Comments.Count((Comments c) => c.PostNavigation.Cap == 3);
if (paarisgoldcomment > 0)
{
Capnoindex = true;
}

How do I change the second one so that I can count the number of c.PostNavigation.Cap that are equal to 3?

Brando Zhang-MSFT 2,956 Reputation points Microsoft Vendor

2021-09-24T01:53:02.463+00:00
Hi @PostAlmostAnything ,

Could you please share the Comments model's makeup? Besides, the Count method normally is used to calculate comments' value. For example this Comments is List<Comment>, then the count function could set some Comment's condition. I suggest you could try this:

int paarisgoldcomment = Comments.Count(c => c.PostNavigation.Cap == 3);

PostAlmostAnything 1

The relevant parts of the comments model look like this:

public partial class Comments
    {
        public int Commentid
        {
            get;
            set;
        }
        public string Comment
        {
            get;
            set;
        }

        public int? Post
        {
            get;
            set;
        }

        public DateTime? Date
        {
            get;
            set;
        }
        public bool Active
        {
            get;
            set;
        }
        public string Userid
        {
            get;
            set;
        }
        public virtual Posts PostNavigation
        {
            get;
            set;
        }

        public virtual ICollection<Images> Images
        {
            get;
            set;
        }

        public virtual ICollection<Likes> Likes
        {
            get;
            set;
        }

        public virtual ICollection<Ratings> Ratings
        {
            get;
            set;
        }
        public Comments()
        {
            Images = new HashSet<Images>();
            Likes = new HashSet<Likes>();
            Ratings = new HashSet<Ratings>();
        }
    }

Then the Posts model has the following relevant part:

public int? Cap
    {
        get;
        set;
    }
public virtual ICollection<Comments> Comments
    {
        get;
        set;
    }
public Posts()
    {
        Comments = new HashSet<Comments>();
        Images = new HashSet<Images>();
        Likes = new HashSet<Likes>();
        Ratings = new HashSet<Ratings>();
    }

PostAlmostAnything 1

The Comments object in the razor page is created by calling:

Comments = await PostService.GetCommentsbyUserName(ApplicationUser.UserName);

The service class contains this:

public async Task<List<Comments>> GetCommentsbyUserName(string username)
     {
         string userid = (await _userManager.FindByNameAsync(username.ToString().ToLower())).Id.ToString();
         return (from p in await GetComments()
                 where p.Userid == userid.ToString()
                 select p into d
                 orderby d.Commentid descending
                 select d).ToList();
     }

PostAlmostAnything 1

The relevant parts of GetComments are as follows:

public async Task<Comments[]> GetComments()
    {
        return await (from c in _context.Comments
                      select c into cs
                      select new Comments
                      {
                          Commentid = cs.Commentid,
                          Comment = cs.Comment,
                          Post = cs.Post,
                          Date = cs.Date,
                          Active = cs.Active,
                          Userid = cs.Userid,
                          PostNavigation = new Posts
                          {
                              Title = cs.PostNavigation.Title,
                              Active = cs.PostNavigation.Active,
                              Cap = cs.PostNavigation.Cap
                          },
                          Ratings = cs.Ratings.Select((Ratings r) => new Ratings
                          {
                              Commentnumber = r.Commentnumber,
                              Rating = r.Rating
                          }).ToArray(),
                          Images = cs.Images.Select((Images i) => new Images
                          {
                              Image = i.Image,
                              Imagename = i.Imagename
                          }).ToArray(),
                          Likes = cs.Likes.Select((Likes l) => new Likes
                          {
                              Likeid = l.Likeid,
                              Commentid = l.Commentid
                          }).ToArray()
                      }).ToArrayAsync();
    }

PostAlmostAnything 1 Reputation point

2021-09-25T06:04:09.367+00:00

I am trying to count the number of posts with a Cap value of 3 from a part of the site that displays comments only.
Brando Zhang-MSFT 2,956 Reputation points Microsoft Vendor

2021-09-28T07:32:14.557+00:00

Could you please tell me what's the result you have always return 0 or you faced some error message?
PostAlmostAnything 1 Reputation point

2021-09-29T05:54:18.68+00:00

No error message. Just 0
Brando Zhang-MSFT 2,956 Reputation points Microsoft Vendor

2021-10-08T05:42:46.83+00:00

Could you please tell me which ORM you have used in your project? EF core or Dapper or else? It seems this is related with lazyloading or something else.
PostAlmostAnything 1 Reputation point

2021-10-11T01:11:26.937+00:00

EF Core