private async Task <IEnumerable <IGrouping <TK, T> > > ApplyGroupingSpecificationAsync <TK>(IGroupingSpecification <T, TK> spec)
{
// must return IEnumerable since GroupBy computation on database is not supported yet in EF Core 3.0
// TODO: change as soon EF Core supports GroupBy
return(await SpecificationEvaluator <T> .GetGroupingEnumerableAsync(DbContext.Set <T>().AsQueryable(), spec));
}
public async Task <IDictionary <TK, IEnumerable <T> > > DictionaryGroupedAsync <TK>(IGroupingSpecification <T, TK> spec)
{
return((await ApplyGroupingSpecificationAsync(spec)).ToDictionary(group => group.Key, group => group.Select(x => x)));
}
internal async static Task <IEnumerable <IGrouping <TK, T> > > GetGroupingEnumerableAsync <TK>(IQueryable <T> inputQuery, IGroupingSpecification <T, TK> specification)
{
if (specification == null)
{
throw new ArgumentNullException(nameof(specification));
}
var query = GetQuery(inputQuery, specification);
if (specification.GroupBy != null)
{
return((await query.ToListAsync()).GroupBy(specification.GroupBy.Compile()));
}
throw new Exception("GroupBy Expression was missing.");
}