Question

I am trying to display a search rank along with the results using MongoDB and the C# driver in an MVC website.
My goal is to display a grid something like this:

1. This is result one
2. This is result two
3. This is result three

My model:

public class Product
{
    [BsonId]
    public string Id { get; set; }

    public string Name { get; set; }

    public int Rank { get; set; }
}

My find code from the repository layer looks like this:

    public IList<TEntity> Find<TEntity>(Expression<Func<TEntity, bool>> criteria) where TEntity : class
    {
        return this.GetQuery<TEntity>().AsQueryable().Where(criteria).ToList<TEntity>();
    }

My controller looks like this:

    public ActionResult Index(string query)
    {
        var model = new SearchModel();

        model.Results = this.Repository.Find<Product>(x => x.Name == “some query”)
          .OrderBy(model.GridSortOptions.Column, model.GridSortOptions.Direction)
          .AsPagination(1, 25);

        return View(model);
    }

The Mongo.Find command needs to populate the model with the each record and calculate the rank (1, 2, 3 etc.).

How do I go about this using the C# driver? I am also using the fluent linq provider.

Answer 1

There is no Rank function in mongodb therefore driver not support it as well. But i guess it not a problem because you can build row rank on the client side when you’ve loaded data or when you will display a grid.

var pagingSkip = 1;
model.Results = this.Repository.Find<Product>(x => x.Name == “some query”)
   .OrderBy(model.GridSortOptions.Column, model.GridSortOptions.Direction)
   .AsPagination(pagingStart, 25);

foreach(var item in model.Results)
{
  item.Rank = pagingSkip + 1;
}