private static IOrderedQueryable <Book> ApplySortOrder <TProperty>
(
Models.QueryRequestSortDirection direction,
IQueryable <Book> query,
Expression <Func <Book, TProperty> > propertyExpression
)
=> direction == Models.QueryRequestSortDirection.Asc
? query.OrderBy(propertyExpression)
: query.OrderByDescending(propertyExpression);
public async Task <IReadOnlyCollection <Models.Identified <Models.Book> > > QueryAsync
(
Models.QueryRequestSortTargetField target,
Models.QueryRequestSortDirection direction
)
{
var items = await CreateQuery().ToArrayAsync();
return(items
.Select
(
item => new Models.Identified <Models.Book>()
{
Id = item.Id,
Value = _mapper.Map <Models.Book>(item)
}
)
.ToArray());
IQueryable <Book> CreateQuery()
{
var query = _context
.Books
.Include(item => item.Authors)
.AsQueryable();
if (target == Models.QueryRequestSortTargetField.Title)
{
Expression <Func <Book, string> > propertyExpression = book => book.Title;
return(ApplySortOrder(direction, query, propertyExpression));
}
else
{
Expression <Func <Book, ushort?> > propertyExpression = book => book.PublicationYear;
return(ApplySortOrder(direction, query, propertyExpression));
}
}
}
