EF7加载列表中实体的子级

John Edwards 发表于 Dev

约翰·爱德华兹

我有如下实体关系：

public class Incident
{
    [Key]
    public int Id { get; set; } 

    public List<Equipment> EquipmentAssignments { get; set; }

}

public class Equipment
{
    public int EquipmentId { get; set; }         
    public Incident Incident { get; set; }
    public Designator Designator { get; set; }//I WANT TO INCLUDE THIS
}

我试图在“ EquipmentAssignments”中为每个设备包括“ Designer”，并返回此列表。我正在尝试以下方法：

 Incident tmp = _context.Incidents
                        .Where(x => x.Id == incid)
                        .Include(x => x.EquipmentAssignments)
                        .ThenInclude(x => x.Select(s => s.Designator)).First();

但我收到以下错误：

附加信息：属性表达式'x => {from x中的Equipment s select [s] .Designator}'无效。该表达式应表示属性访问：“ t => t.MyProperty”。指定多个属性时，请使用匿名类型：'t => new {t.MyProperty1，t.MyProperty2}'。

我尝试使用匿名类型.ThenInclude(x => x.Select(s => new { s.Designator})无济于事，并且不确定如何完成我所需要的。感谢您的任何帮助。

巴萨姆·阿鲁吉利（Bassam Alugili）

您不能在ThenInclude中传递选择。这是ThenInclude语法：

public static IIncludableQueryable<TEntity, TProperty> ThenInclude<TEntity, TPreviousProperty, TProperty>(this IIncludableQueryable<TEntity, ICollection<TPreviousProperty>> source, Expression<Func<TPreviousProperty, TProperty>> navigationPropertyPath) where TEntity : class;

只需删除选择，一切都会正常！

  var tmp = myConext.Incidents
          .Where(x => x.Id == 1)
          .Include(x => x.EquipmentAssignments)
          .ThenInclude(x => x.Designator).First();

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