c# - Entity Framework linq 包含和分组

Question

这个问题已经有答案了:

Why doesn't Include have any effect? (2 个回答)

已关闭 2 年前。

我正在尝试在一个句子中包含和分组

var instanceIdList = context.
    Tracks.
    Include("Services").
    GroupBy(x => x.ServiceId).
    Take(top);

但是当我在调试时检查结果时，我看不到任何包含值

我尝试用另一种方式来做

var objectContext = ((IObjectContextAdapter)context).ObjectContext;
var set = objectContext.CreateObjectSet<Track>();
var instanceIdList = set.Include("Services").GroupBy(x => x.ServiceId);

这是类(class): 追踪

  public partial class Track
{
    public long Id { get; set; }
    public System.Guid ServiceId { get; set; }
    public Nullable<System.Guid> ServiceInterfaceId { get; set; }
    public Nullable<System.Guid> ProviderId { get; set; }
    public System.Guid ServiceInstanceId { get; set; }
    public System.Guid ActivityParentId { get; set; }
    public System.Guid ActivityInstanceId { get; set; }
    public int ActivityType { get; set; }
    public int ServiceRole { get; set; }
    public int TrackOrder { get; set; }
    public System.DateTime Datetime { get; set; }
    public Nullable<System.Guid> MessageId { get; set; }
    public int Status { get; set; }
    public Nullable<int> ESBErrorCode { get; set; }
    public Nullable<int> ESBTecnicalErrorCode { get; set; }
    public string ErrorDescription { get; set; }
    public string PortName { get; set; }
    public string MachineName { get; set; }
    public string ConsumerId { get; set; }
    public string ExternalId { get; set; }
    public string ConsumerMachineName { get; set; }
    public int ServiceBehavior { get; set; }

    public virtual Message Message { get; set; }
}

服务

      public partial class Service
      {
        public Service()
        {
        this.Providers = new HashSet<Provider>();
        this.ServiceInterfaces = new HashSet<ServiceInterface>();
            }

    public System.Guid ServiceId { get; set; }
    public string ServiceName { get; set; }
    public string ServiceNumber { get; set; }
    public Nullable<System.Guid> ModelSchemaId { get; set; }

    public virtual ICollection<Provider> Providers { get; set; }
    public virtual ICollection<ServiceInterface> ServiceInterfaces { get; set; }
}

但是结果是一样的

谢谢

三木

Answer 1

您还需要将 include 放在最后。

像这样...

var instanceIdList = context.Tracks
                            .GroupBy(x => x.ServiceId)
                            .Take(top)
                            .Include("Services");