实体框架核心 - 子类值为null

Question

I have one DBSet for all my child classes -> base class is EventModel. When i try to load all EventUpdateCartModel (One child class from EventModel) with all datas the child datas always null. The base values are available like SettingsModel or AccountModel.

** My Question:**

How can i load all datas with the base class DbSet and not with the child class DbSet.

Classes

public abstract class EventModel
{

 ... Some Other Datas
 public virtual SettingsModel SettingsModel { get; set; }
 public virtual AccountModel AccountModel { get; set; }
}

public class EventUpdateCartModel : EventModel
{
  public virtual UpdateCartDataModel UpdateCartDatas { get; set; }
}

public class UpdateCartDataModel
{
  public long UpdateCartDataId { get; set; }
  public EventUpdateCartType Action { get; set; }  
}

DbSet

  public DbSet<EventModel> Events { get; set; }

Read Rows

 var events = context.Events.ToList();

When i add a new DbSet for the child class and try to get the value with this DbSet all values are available.

DbSet

 public DbSet<EventUpdateCartModel> Events_UpdateCart{ get; set; }

Read Rows

var events = context.Events_UpdateCart.ToList();

** My Question:**

How can i load all datas with the base class DbSet and not with the child class DbSet.

I hope somebody can help me.

Answer 1

One approach would be to change your query to return an anonymous type that only includes the necessary fields from your model and omit the child DbSet. For example:

var events = context.Events_UpdateCart
                .Select(u => new {
                      EventId = u.EventId,
                      EventType = u.EventType
                });

Read more on the EF core docs .