AutoMapper with EF Core doesn't return OData #count correctly if using $top - entity-framework

Question

I'm using the solution provided by this link: AutoMapper don't work with entity EF Core
My problem is when using $top, #odata.count always return the number informed in $top but should return the number of total record.
I know that ODataQueryOptions has a property “Count”, but I don't know if it's possible to use to solve the problem
I'm using the below the code provided by Дмитрий Краснов in his question including the solution by Ivan Stoev:
There is entities:
public class LessonCatalog {
public string Name { get; set; }
public int? ImageId { get; set; }
public virtual Image Image { get; set; }
public virtual ICollection<Lesson> Lessons { get; set; }
}
public class Lesson {
public string Name { get; set; }
public string Description { get; set; }
public int? ImageId { get; set; }
public virtual Image Image { get; set; }
public int LessonCatalogId { get; set; }
public virtual LessonCatalog LessonCatalog { get; set; }
}
Views:
public class LessonView {
public string Name { get; set; }
public string Description { get; set; }
public int? ImageId { get; set; }
public ImageView Image { get; set; }
public int LessonCatalogId { get; set; }
public LessonCatalogView LessonCatalog { get; set; }
}
public class LessonCatalogView {
public string Name { get; set; }
public int? ImageId { get; set; }
public ImageView Image { get; set; }
public IEnumerable<LessonView> Lessons { get; set; }
}
My maps:
CreateMap<LessonCatalog, LessonCatalogView>()
.ForMember(dest => dest.Image, map => map.ExplicitExpansion())
.ForMember(dest => dest.Lessons, map => map.ExplicitExpansion());
CreateMap<Lesson, LessonView>()
.ForMember(dest => dest.LessonCatalog, map => map.ExplicitExpansion());
In my repository:
protected readonly DbContext _context;
protected readonly DbSet<TEntity> _entities;
public Repository(DbContext context) {
_context = context;
_entities = context.Set<TEntity>();
}
public IEnumerable<TView> GetOData<TView>(ODataQueryOptions<TView> query,
Expression<Func<TEntity, bool>> predicate = null) {
IQueryable<TEntity> repQuery = _entities.AsQueryable();
IQueryable res;
if (predicate != null) repQuery = _entities.Where(predicate);
if (query != null) {
string[] expandProperties = GetExpands(query);
//!!!
res = repQuery.ProjectTo<TView>(Mapper.Configuration, null, expandProperties);
//!!!
var settings = new ODataQuerySettings();
var ofilter = query.Filter;
var orderBy = query.OrderBy;
var skip = query.Skip;
var top = query.Top;
if (ofilter != null) res = ofilter.ApplyTo(res, settings);
if (orderBy != null) res = orderBy.ApplyTo(res, settings);
if (skip != null) res = skip.ApplyTo(res, settings);
if (top != null) res = top.ApplyTo(res, settings);
} else {
res = repQuery.ProjectTo<TView>(Mapper.Configuration);
}
return (res as IQueryable<TView>).AsEnumerable();
}
If my query result has 1007 records, and I use
…$count=true&$top=5
the result for count should be
"#odata.count": 1007
But instead the result is always
"#odata.count": 5
Using SQL Server Profile I can see that the Select for count is including the “top”. So, how to avoid this to happen?

Answer 1

I received a help from the Github Guy (thanks to #Gennady Pundikov) and could now answer this question.
I changed the GetOData Method to get the Count before apply others settings:
public IEnumerable<TView> GetOData<TView>(ODataQueryOptions<TView> query,
Expression<Func<TEntity, bool>> predicate = null) {
IQueryable<TEntity> repQuery = _entities.AsQueryable();
IQueryable res;
if (predicate != null) repQuery = _entities.Where(predicate);
if (query != null) {
string[] expandProperties = GetExpands(query);
//!!!
res = repQuery.ProjectTo<TView>(Mapper.Configuration, null, expandProperties);
//!!!
var settings = new ODataQuerySettings();
var ofilter = query.Filter;
var orderBy = query.OrderBy;
var skip = query.Skip;
var top = query.Top;
if (ofilter != null) res = ofilter.ApplyTo(res, settings);
if (query.Count?.Value == true)
{
// We should calculate TotalCount only with filter
// http://docs.oasis-open.org/odata/odata/v4.0/odata-v4.0-part2-url-conventions.html#_Toc371341773
// 4.8 Addressing the Count of a Collection
// "The returned count MUST NOT be affected by $top, $skip, $orderby, or $expand.
query.Request.ODataFeature().TotalCount = ((IQueryable<TView>)res).LongCount();
}
if (top != null) res = top.ApplyTo(res, settings);
if (orderBy != null) res = orderBy.ApplyTo(res, settings);
if (skip != null) res = skip.ApplyTo(res, settings);
} else {
res = repQuery.ProjectTo<TView>(Mapper.Configuration);
}
return (res as IQueryable<TView>).AsEnumerable();
}