[英]Linq select tablemapping(Entity framework)
我有以下表格
**Track Table**
+---------------+---------------+--------------------+
| TrackId | TrackName | Path |
+===============+===============+====================+
| 1 | jb | http://domain/1.mp3|
+---------------+---------------+--------------------+
| 2 | remix | http://domain/2.mp3|
+---------------+---------------+--------------------+
**Favorite Table**
+---------------+---------------+--------------------+
| favoriteId | ProfileId | TrackId |
+===============+===============+====================+
| 10 | 2130 | 1 |
+---------------+---------------+--------------------+
| 11 | 2132 | 2 |
+---------------+---------------+--------------------+
我需要将曲目选择到一个模型中,我必须在其中包含一个布尔字段IsFavorite
。 现在我的逻辑如下:
1.Select Tracks
2.Select all favorites by profile
3.Iterate to both list and fill field "IsFavorite"
有没有更好的方法可以解决相同的问题?
以下是我当前的逻辑代码
Var ActiveTracks = jukeboxTrackService.GetActiveTracks();
var UserFavorites = jukeboxTrackService.GetFavoritesByProfile(ProfileId);
foreach (var item in ActiveTracks )
{
foreach (var fav in UserFavorites)
{
if (item.JukeBoxTrackId == fav.TrackId)
{
item.IsFavorite = true;
}
}
}
return ActiveTracks ;
提前致谢。
(from tr in ActiveTracks
join usrfav in UserFavorites on tr.TrackId equals usr.TrackId into UsrTracks
from usrtr in UsrTracks.DefaultIfEmpty()
select new Track
{
IsFavorite = (usrfav.TrackId == null) ? false : true
}
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