c# - 如何使用 linq to entities 获取字符串数组或 JSON 格式的数据？

Question

我有一个 ASP.Net MVC5 站点并使用 EF 6.0

一对多关系

这是我的模型

public class Singer
{
    [Key]
    public int SingerID { get; set; }

    public string SingerName { get; set; }

    public virtual List<Album> Albums { get; set; }
}

public class Album
{
    [Key]
    public int AlbumID { get; set; }

    public string AlbumName { get; set; }

    public string AlbumDate { get; set; }

    [ForeignKey("Singer")]
    public int SingerID { get; set; }

    public virtual Singer Singer { get; set; }
}

现在我的 Linq 如下所示

public IEnumerable<T> GetAlbums()
{
    using (dbContext db = new dbContext())
    {
        IQueryable<T> query = (from c in db.Albums
                               group c.AlbumId by c.SingerId into albums
                               select new AlbumMapper()
                               {
                                   AlbumID = albums.Key,
                                   Total = albums.Count()
                               })
        }
}

在当前场景中，我获取了按 albumId 和专辑数量分组的所有专辑。

但我的需要是形成如下所示的 JSON 字符串

[
   {
      "SingerID":1,
      "Albums":[
         {
            "AlbumName":"This is Album 1",
            "AlbumDate":"Dec 30,2015"
         },
         {
            "AlbumName":"This is Album 2",
            "AlbumDate":"Dec 30 2015"
         }
      ]
   },
   {
      "SingerID":2,
      "Albums":[
         {
            "AlbumName":"This is Album 1",
            "AlbumDate":"Dec 30,2015"
         },
         {
            "AlbumName":"This is Album 2",
            "AlbumDate":"Dec 30 2015"
         }
      ]
   }
]

添加映射器类

public class AlbumDetails
{
   public DateTIme AlbumDate

   public string AlbumName

}

public class AlbumMapper
{
    public int AlbumID

    public IEnumerable<AlbumDetails> Albums  
}

Answer 1

只需将所有歌手放入列表并使用 Json.NET ( http://www.newtonsoft.com/json ) 将其序列化

如果您想省略 SingerName，请务必向属性添加 [JsonIgnore] 数据属性