[英]Automapper - Bestpractice of mapping a many-to-many association into a flat object
I have two entities: Employee
and Team
. 我有两个实体: Employee
和Team
。
What I want is an EmployeeForm
that has the Name
of the Team
. 我想要的是一个拥有Team
Name
的EmployeeForm
。
How can I achieve this using AutoMapper ? 如何使用AutoMapper实现此目的?
My current "solution" is the following: 我目前的“解决方案”如下:
Mapper.CreateMap<Employee, EmployeeForm>()
.ForMember(dest => dest.TeamName, opt => opt.MapFrom(x => x.GetTeams().FirstOrDefault() != null ? string.Join(", ", x.GetTeams().Select(y=>y.Name)) : "n/a"));
In my opinion this is bad readable. 在我看来,这是可读的。
What I would like to have is a generic method where I can pass an entity, choosing the collection and saying if collection is null return a default value or otherwise choose the property of the collection via lambda expressions. 我想要的是一个通用方法,我可以传递一个实体,选择集合并说集合是否为null返回默认值,或者通过lambda表达式选择集合的属性。
I rethinked my whole design starting to change the domain model : 我重新考虑我的整个设计开始更改域模型 :
I changed the many-to-many association
into two one-to-many associations
using a relation table. 我改变了many-to-many association
成两个one-to-many associations
使用关系表。
With this more easier domain model , I can easily map this into a flat DTO using AutoMapper . 使用这个更简单的域模型 ,我可以使用AutoMapper轻松将其映射到平面DTO 。
public class TeamEmployeeMapperProfile : Profile
{
protected override void Configure()
{
CreateMap<TeamEmployee, TeamEmployeeForm>();
}
}
Yes that's all :) 是的,这就是:)
Here is the flat view model object. 这是平面视图模型对象。
You could create a read-only string property on Employee called "TeamNames". 您可以在Employee上创建一个名为“TeamNames”的只读字符串属性。 Put the list-building logic in there. 将列表构建逻辑放在那里。 That way, you've got a property that is testable (vs. the lambda expression) and it will make your mapping easier. 这样,你就拥有了一个可测试的属性(与lambda表达式相比),它将使你的映射更容易。
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