I'm trying to use AutoMapper to flatten multiple levels of arrays.
Consider the following source classes:
class X {
public string A { get; set; }
public Y[] B { get; set; }
}
class Y {
public string C { get; set; }
public Z[] D { get; set; }
}
class Z {
public string E { get; set; }
public string F { get; set; }
}
And the following destination:
class Destination {
public string A { get; set; }
public string C { get; set; }
public string E { get; set; }
public string F { get; set; }
}
What I'd like to be able to do is get a List from one or more X, e.g.:
Mapper.Map<IEnumerable<X>, IEnumerable<Destination>>(arrayOfX);
I'm unable to figure out what sort of mapping configuration to use to achieve this. MapFrom seems like the way to go for 1:1 compositions, but doesn't seem to be able to handle the array (or other enumerable) unless I use AutoMapper's destination naming convention.
Any insights on how to achieve this?
Try this mapper,
Mapper.CreateMap<Z, Destination>();
Mapper.CreateMap<Y, Destination>();
Mapper.CreateMap<X, Destination>()
.ForMember(destination => destination.A, options => options.MapFrom(source => source.A)).IgnoreAllNonExisting()
.ForMember(destination => destination.C, options => options.MapFrom(source => Mapper.Map<IEnumerable<Y>, IEnumerable<Destination>>(source.B).FirstOrDefault().C))
.ForMember(destination => destination.E, options => options.MapFrom(source => Mapper.Map<IEnumerable<Z>, IEnumerable<Destination>>(source.B.SelectMany(d => d.D)).FirstOrDefault().E))
.ForMember(destination => destination.F, options => options.MapFrom(source => Mapper.Map<IEnumerable<Z>, IEnumerable<Destination>>(source.B.SelectMany(d => d.D)).FirstOrDefault().F));
var result = Mapper.Map<IEnumerable<X>, IEnumerable<Destination>>(arrayOfX);
I had a very similar problem a while ago. I had a collection of locations, and each location had a collection of streets. I wanted to map them to a collection of view models where each view model represented a street (including the location details).
This was my solution: https://groups.google.com/forum/#!topic/automapper-users/b66c1M8eS8E
For this particular problem, this could be your mapping configuration:
public static class AutoMapperConfig
{
public static void Configure()
{
Mapper.CreateMap<Z, Destination>()
.ForMember(dest => dest.A, opt => opt.Ignore())
.ForMember(dest => dest.C, opt => opt.Ignore());
Mapper.CreateMap<Y, Destination>()
.ForMember(dest => dest.A, opt => opt.Ignore())
.ForMember(dest => dest.E, opt => opt.Ignore())
.ForMember(dest => dest.F, opt => opt.Ignore());
Mapper.CreateMap<X, Destination>()
.ForMember(dest => dest.C, opt => opt.Ignore())
.ForMember(dest => dest.E, opt => opt.Ignore())
.ForMember(dest => dest.F, opt => opt.Ignore());
}
}
Because AutoMapper is primarily a 1:1 mapping, you need to implement a wee bit of magic to map to multiple objects. This is an example of how you could call that mapping to populate your object:
var rc = data.SelectMany(
x => x.B.SelectMany(
y => y.D
.Select(Mapper.Map<Z, Destination>)
.Select(z => Mapper.Map(y, z))
)
.Select(y => Mapper.Map(x, y))
);
Here are a couple of unit tests to validate the mapping and show it in action:
[TestFixture]
public class MapperTests
{
[Test]
public void Mapping_Configuration_IsValid()
{
AutoMapperConfig.Configure();
Mapper.AssertConfigurationIsValid();
}
[Test]
public void Mapping_TestItems_MappedOK()
{
AutoMapperConfig.Configure();
Mapper.AssertConfigurationIsValid();
var data = new[]
{
new X
{
A = "A1",
B = new[]
{
new Y
{
C = "A1C1",
D = new[]
{
new Z
{
E = "A1C1E1",
F = "A1C1F1"
},
new Z
{
E = "A1C1E2",
F = "A1C1F2"
},
}
},
new Y
{
C = "A1C2",
D = new[]
{
new Z
{
E = "A1C2E1",
F = "A1C2F1"
},
new Z
{
E = "A1C2E2",
F = "A1C2F2"
},
}
}
}
}
};
var rc = data.SelectMany(
x => x.B.SelectMany(
y => y.D
.Select(Mapper.Map<Z, Destination>)
.Select(z => Mapper.Map(y, z))
)
.Select(y => Mapper.Map(x, y))
);
Assert.That(rc, Is.Not.Null);
Assert.That(rc.Count(), Is.EqualTo(4));
var item = rc.FirstOrDefault(x => x.F == "A1C2F2");
Assert.That(item, Is.Not.Null);
Assert.That(item.A, Is.EqualTo("A1"));
Assert.That(item.C, Is.EqualTo("A1C2"));
Assert.That(item.E, Is.EqualTo("A1C2E2"));
Assert.That(item.F, Is.EqualTo("A1C2F2"));
}
}
For anyone else coming across this post by searching how to Flatten object structure with AutoMapper - the new AutoMapper supports flattening with IncludeMembers() syntax.
Source: http://docs.automapper.org/en/stable/Flattening.html
So the original issue could be solved like this:
Mapper.CreateMap<Z, Destination>();
Mapper.CreateMap<Y, Destination>().IncludeMembers(src => src.D);
Mapper.CreateMap<X, Destination>().IncludeMembers(src => src.B);
来源：https://stackoverflow.com/questions/13338262/automapper-and-flattening-nested-arrays