Question

我的QueryOver出现问题，我不明白为什么。我的查询返回viewmodel对象ContactInfo。我在Employee属性上收到此错误：“找不到属性的setter”。如何填写ContactInfo中的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与默认不同的结果转换器，例如DeepTransformer。

在这种情况下，查询必须使用与DTO模型类似的别名。因此，如果我们的域属性ei.FirstName属于 JoinAlias - j.EmployeeInfo，则别名必须反映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＆＃34; EmployeeInfo.FirstName＆＃34; 将用于将Employee填充为属性 EmployeeInfo 及其属性 FirstName

此结果转换器

DeepTransformer

DeepTransformer将使用Alias来构建参考树。可用于many-to-one ... 的引用/ IDictionary（但不适用于集合）

注意：.Is()方法来自某些扩展程序，可以替换为with != null，如

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

NHibernate QueryOver在父对象中使用投影填充属性对象

1 个答案: