Question

I have a problem displaying most popular tags from database in view. I’m not sure about this question title so if someone has a better one please do rename it.

Scenario

I need to show recent posts, recent galleries and most popular tags on my index page. I decided to use tuples for this and it worked fine until I tried to show most popular tags.

Error

The model item passed into the dictionary is of type
‘System.Tuple3[photoBlog.Models.Gallery[],photoBlog.Models.Post[],System.Linq.IGrouping2[System.Int32,photoBlog.Models.PostTag][]]’,
but this dictionary requires a model item of type
‘System.Tuple`3[photoBlog.Models.Gallery[],photoBlog.Models.Post[],photoBlog.Models.PostTag[]]’.

As you can see it gives my view wrong object type. I want expect it to be an array, but it gives me some kind of System.Linq.Grouping item.

Code

As you can see I convert it into array in my controller.

public ActionResult Index()
{
    photoBlogModelDataContext _db = new photoBlogModelDataContext();
    var posts = _db.Posts.OrderByDescending(x => x.DateTime).Take(4).ToArray();
    var galleries = _db.Galleries.OrderByDescending(x => x.ID).Take(4).ToArray();
    var posttags = _db.PostTags.GroupBy(x => x.TagID).OrderBy(x => x.Count()).Take(4).ToArray();
    return View(Tuple.Create(galleries, posts, posttags));
}

My view is straight forward, note that this did work until I tried to add most popular tags.

@model Tuple<photoBlog.Models.Gallery[], photoBlog.Models.Post[], photoBlog.Models.PostTag[]>
@foreach (var tag in Model.Item3)
{ 
    @tag.Tag.Name
}

Answer 1

You probably want

var posttags = _db.PostTags
    .GroupBy(x => x.TagID)
    .OrderBy(x => x.Count())
    // Take each group and pass the first tag of the group
    .Select(g => g.First())
    .Take(4)
    .ToArray();

At the moment you’re passing e.g. all 8 instances of the most popular tag, all 5 instances of the second most popular, etc., each in their own group. I imagine you just want to pass an “example” of each tag.