NHibernate的QueryOver使用投影在父對象中填充屬性對象

Question

我的QueryOver出現問題，我不明白爲什麼。我的查詢返回viewmodel對象ContactInfo。我在Employee屬性上遇到此錯誤：「無法找到屬性的setter」。我如何在ContactInfo中填充Employee屬性？我究竟做錯了什麼？

視圖模型對象：

public class ContactInfo  
{ 
    public EmployeeInfo Employee { get; set; } 
    public string Email { get; set; } 
    public string InternalTelephone { get; set; } 
} 

查詢

public override ContactInfo Execute() 
    { 
     ContactInfo r = null; 
     EmployeeInfo ei = null; 

     var result = Session.QueryOver<Job>() 
      .JoinAlias(j => j.EmployeeInfo,() => ei) 
      .Where(j => j.EmployeeInfo.Id == _employeeId) 
      .Select(
       Projections.Property<Job>(j => ei.Id).WithAlias(() => r.Employee.Id), 
       Projections.Property<Job>(j => ei.FirstName).WithAlias(() => r.Employee.FirstName), 
       Projections.Property<Job>(j => ei.LastName).WithAlias(() => r.Employee.LastName), 
       Projections.Property<Job>(j => ei.ReferenceCode).WithAlias(() => r.Employee.ReferenceCode), 
       Projections.Property<Job>(j => j.Telefoon).WithAlias(() => r.InternalTelephone) 
      ) 
      .TransformUsing(Transformers.AliasToBean<ContactInfo>()) 
      .Take(1) 
      .SingleOrDefault<ContactInfo>(); 

     var email = Session.QueryOver<Employee>() 
      .Where(e => e.Id == _employeeId) 
      .Select(e => e.Email) 
      .SingleOrDefault<string>(); 

     result.Email = email; 

     return result; 
    } 
} 

Answer 1

我們可以做的比默認結果變壓器，例如使用不同DeepTransformer。

在這種情況下，查詢必須使用類似於DTO模型的別名。所以，如果我們有屬於JoinAlias域屬性ei.FirstName - j.EmployeeInfo - 別名必須反映DTO的ContactInfo - "EmployeeInfo.FirstName"

.Select(  
    Projections.Property<Job>(j => ei.FirstName)   // the mapped domain model 
          .As("EmployeeInfo.FirstName"), // the path in DTO/view model 
    ... 
) 
.TransformUsing(DeepTransformern<ContactInfo>()) // the DTO 

所以現在，路徑「EmployeeInfo.FirstName」將被用於填充在Employee作爲屬性EmployeeInfo及其財產姓

這一結果變壓器

• DeepTransformer

DeepTransformer將使用別名來建立參考樹。可用於引用/ many-to-one以及用於IDictionary ... （但不包括收藏品）

注：.Is()方法來源於一些擴展，並且可以更換with != null像

public static partial class Ext 
{ 
    public static bool Is(this object value) 
    { 
     return value != null; 
    } 
....