c# - NHibernate QueryOver 用投影填充父对象中的属性对象

Question

我的 QueryOver 有问题，我不明白为什么。我的查询返回 View 模型对象 ContactInfo。我在 Employee 属性上收到此错误:“找不到属性的 setter ”。如何在 ContactInfo 中填写 Employee 属性？我做错了什么？

ViewModel 对象:

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

查询

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

我们可以做的是使用不同于默认的结果转换器，例如DeepTransformer .

在那种情况下，查询必须使用类似于 DTO 模型的 Alias。因此，如果我们有属于 JoinAlias 的域属性 ei.FirstName - j.EmployeeInfo - 别名必须反射(reflect) DTO 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

现在，路径 "EmployeeInfo.FirstName" 将用于填充 Employee 作为属性 EmployeeInfo 及其属性 FirstName

还有这个结果转换器

• DeepTransformer

DeepTransformer 将使用 Alias 来构建引用树。可用于引用/多对一以及IDictionary ...(但不适用于集合)

注意:.Is() 方法来自一些扩展，可以用 != null 代替

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