EF6 sp 반환셋을 group by 할때

var result = (from r in (connect.Edumate.sMessageReceive(data.startDate, data.endDate, studentList, "", "")

.Select(x => new ListItem { Content = x.Content, RegistDate = x.RegistDate }))

group r by r.Content into g

select new

{

Content = g.Key,

RegistDate = g.Select(x => x.RegistDate).Distinct().FirstOrDefault()

}

);