如何从C＃中的模型列表中删除空值元素？

Question

我尝试使用LINQ查询提取数据并添加到模型列表中。在此列表中，我只需要一些字段值，但它返回所有表字段包括空值。我使用模型第一种方法，所以所有模型类都将创建带有所有表字段名称的get set方法，所以我想在检索数据时删除一些字段是否可能？

这是我的代码

for (var z = 0; z < room_ament_list.Count(); z++)    
{
     var deal_room_amentity_id = room_ament_list[z];
     var deal_room_amentity_details = db.deal_room_amentity.Where(a => a.room_amenity_id == deal_room_amentity_id).ToList();

     foreach (var item_r_amentity in deal_room_amentity_details)
     {
         deal_room_amentity_list.Add(new deal_room_amentity()
         {
           room_amenity_id = item_r_amentity.room_amenity_id,
           amenity_type = item_r_amentity.amenity_type,
         });
     }
}

这是我的表结构

这是从该列表中返回数据

但是我需要提取我在列表中指定的数据（没有null元素）。是否可以从列表中删除那些空值元素？

Answer 1

如果我正确理解您的问题，您可以修改LINQ查询，如下所示：

var deal_room_amentity_details = db.deal_room_amentity
     .Where(a => a.room_amenity_id == deal_room_amentity_id 
     && a.room_amenity_id != null).ToList();

Answer 2

您可以通过在Linq查询中指定对象定义，从SQL表中下载所需的信息。

 var data = from x in db.deal_room_amentity
         where 
              x.room_amenity_id == deal_room_amentity_id
         select new {
              id = x.id,
              room_amenity_id = x.room_amenity_id
         };
    foreach(var item_r_amentity in data){
         deal_room_amentity_list.Add(new deal_room_amentity()
             {
               room_amenity_id = item_r_amentity.room_amenity_id,
               amenity_type = item_r_amentity.amenity_type,
             });
    }