linq to entity GroupBy多个字段

var items = _voteRecordRepository.GetAll()
            .Where(x => programIds.Contains(x.ProgrammeId))
            .GroupBy(x=>new {x.ClientType,x.ProgrammeId})
            .Select((group)=>new ProgramVoteRecordSelectItem()
            {
                ProgramId = group.Key.ProgrammeId,
                GetVote=group.Count(),
                ClientType=group.Key.ClientType
            })
            .ToList();

IGrouping<TKey, TElement>资料

https://msdn.microsoft.com/zh-cn/library/windows/apps/bb343251(v=vs.95).aspx