LINQ to Entities 不识别方法“System.String ToString()”，因此该方法无法转换为存储表达式

[skystore]

我使用了linq to entity 分组查询 , 结果不知道怎么转换结果,toString() 后报错

源码:

                var images = from img in db.Images
                       where img.UserId == user.UserId
                       group img by img.GalleryId into g
                       select new { 
                           GalleryId = g.Key,
                           Title = g.OrderBy( t => t.ImageId ).Take(1).ToString(),
                           Description = g.OrderBy(t => t.ImageId).Take(1).ToString(),
                           Path = g.OrderBy(t => t.ImageId).Take(1).ToString(),
                           ImageId = Convert.ToInt32(g.OrderBy( t=> t.ImageId).Take(1))
                       };

          
  怎么遍历 images, 想给Photo 类赋值,  运行时报错LINQ to Entities 不识别方法“System.String ToString()”，,该怎么办? 
 foreach (var img in imgages)
                {
                    int k = i % 3;
                    if( k ==0 ){
                        list1.Add(new Photo { Description = img.Description, ImageId = img.ImageId, GalleryId = img.GalleryId,
                                              Path = img.Path, column = k, PhotoNum = photoNum, Title = img.Title});
                    }

Photo 类:

    /// <summary>
    /// 相册模型
    /// </summary>
    public class Photo
    {
        [Key]
        public int ImageId { get; set; }

        public int PhotoNum { get; set; }

        public string Title { get; set; }

        public string Description { get; set; }

        public string Path { get; set; }

        public int UserId { get; set; }

        public int column { get; set; }

        public int GalleryId { get; set; }
    }

[threenewbee]

var images = (from img in db.Images where img.UserId == user.UserId group img by img.GalleryId into g select g).AsEnumerable().Select(g => new { GalleryId = g.Key, Title = g.OrderBy( t => t.ImageId ).Take(1).ToString(), Description = g.OrderBy(t => t.ImageId).Take(1).ToString(), Path = g.OrderBy(t => t.ImageId).Take(1).ToString(), ImageId = Convert.ToInt32(g.OrderBy( t=> t.ImageId).Take(1)) });

[q107770540]

你的错误在于：
group by.. into g后，g是个集合,
g.OrderBy( t => t.ImageId ).Take(1) 这是取集合内的第一个对象， 不应该针对对象进行 tostring()操作

var images = from img in db.Images
                       where img.UserId == user.UserId
                       group img by img.GalleryId into g
                       let x=g.OrderBy(t => t.ImageId ).Take(1)
                       select new { 
                           GalleryId = g.Key,
                           Title = x.Title,
                           Description =x.Description,
                           Path = x.Path,
                           ImageId =x.ImageId
                       };