Issue merging objects with AutoMapper - automapper

I found this post describing how to conditionally copy values over a destination object if they are not null.
Works great except for list members, it always overwrites them with an empty list. I'm not sure if I've just not configured the mapper correctly or if this is a bug. The following program demonstrates the issue.
namespace automapper_test
{
using AutoMapper;
using System;
using System.Collections.Generic;
class Program
{
class Test
{
public int? A { get; set; }
public string B { get; set; }
public Guid? C { get; set; }
public List<Guid> D { get; set; }
}
static void Main(string[] args)
{
var config = new MapperConfiguration(cfg =>
{
cfg.AllowNullCollections = true;
cfg.CreateMap<Test, Test>().ForAllMembers(opt => opt.Condition((src, dest, member) => member != null));
});
var mapper = config.CreateMapper();
var source = new Test { A = 2, C = Guid.Empty };
var target = new Test { A = 1, B = "hello", C = Guid.NewGuid(), D = new List<Guid> { Guid.NewGuid() } };
mapper.Map(source, target);
System.Diagnostics.Debug.Assert(target.D.Count == 1);
}
}
}

Related

Generic Automapper function with custom convension for underscored properties

I simply need to map some auto generated classes from database to domain/viewmodels classes. The autogenerated class may have names like customer_id that I want to be mapped with CustomerId. Somehow I want to register my own convention with auto mapper. I have started with following code however the mapped object properties are not populated:
// Generic method that should map source to target
public static TTarget MapWithUnderScoreConvension(TSource source, TTarget target)
{
Mapper.Initialize(cfg=> cfg.AddProfile<AutoMapperUnderScoreProfile>());
Mapper.CreateMap<TSource, TTarget>();
var mapped = Mapper.Map(source, target);
return mapped;
}
// New underscore profile
public class AutoMapperUnderScoreProfile : Profile
{
public AutoMapperUnderScoreProfile()
{
Mapper.Initialize(configuration => configuration.CreateProfile("UnderScoreProfile", UnderScoreProfile));
Mapper.AssertConfigurationIsValid();
}
private void UnderScoreProfile(IProfileExpression profile)
{
profile.SourceMemberNamingConvention = new PascalCaseNamingConvention();
profile.DestinationMemberNamingConvention = new SourceUnderScoreNamingConvension();
}
}
// Convention class
public class SourceUnderScoreNamingConvension : INamingConvention
{
private readonly string _separatorCharacter="_";
private readonly Regex _splittingExpression = new Regex(#"[\p{Lu}0-9]+(?=_?)");
public Regex SplittingExpression { get { return _splittingExpression;} private set{} }
public string SeparatorCharacter { get { return _separatorCharacter; } private set{} }
}
// Test cases
[TestMethod()]
public void Test_Map_Db_Generated_Class_To_Model()
{
var dbGenerated = new QuestionTypeFromDb()
{
QuestionType_Description = "1",
QuestionType_Id = 1,
QuestionType_Is_Default = true,
QuestionType_Is_TimeBased = true,
QuestionType_Sequence = 1,
QuestionType_Time_In_Seconds = 1
};
var mappedObject = AutoMapperHelper<QuestionTypeFromDb, QuestionType>
.MapWithUnderScoreConvension(dbGenerated, new QuestionType());
mappedObject.QuestionTypeId.Should().Be(dbGenerated.QuestionType_Id);
mappedObject.QuestionTypeDescription.Should().Be(dbGenerated.QuestionType_Description);
mappedObject.TimeInSeconds.Should().Be(dbGenerated.QuestionType_Time_In_Seconds);
mappedObject.QuestionTypeSequence.Should().Be(dbGenerated.QuestionType_Sequence);
}
public class TestQuestionWithAnswerType
{
public int QuestionTypeId { get; set; }
public string QuestionTypeDescription { get; set; }
public int QuestionTypeSequence { get; set; }
public bool QuestionTypeIsTimeBased { get; set; }
public int? QuestionTypeTimeInSeconds { get; set; }
public bool QuestionTypeIsDefault { get; set; }
}
any comments will be appreciated.
Update
I have found that the following workaround works:
I simply replaced used this -> to replace 'underscore' with nothing (Mapper.Initialize(c => c.ReplaceMemberName("_", ""));
public static TTarget MapWithUnderScoreConvension(TSource source, TTarget target)
{
Mapper.Initialize(c => c.ReplaceMemberName("_", ""));
//Mapper.Initialize(cfg => cfg.AddProfile<AutoMapperUnderScoreProfile>());
Mapper.CreateMap<TSource, TTarget>();
var mapped = Mapper.Map(source, target);
return mapped;
}
Your regex needs to be changed to : [\p{L}}0-9]+(?=_?)
This will take care of Customer_Id, CUSTOMER_ID, customer_id
The {L} unicode category includes Lu, Lt, Ll, Lm and Lo characters as mentioned here.
Answer is added in the Update section of the question. Basically the solution for me was very simple -> Mapper.Initialize(c => c.ReplaceMemberName("_", ""));

Restore < AutoMapper 3.1 null -> empty array behaviour

With AutoMapper <= 3.0, this following test passes.
public class AutoMapperTest
{
static Source source;
static Destination destination;
Establish context = () =>
{
Mapper.Configuration.AllowNullCollections = false;
Mapper.CreateMap<Source, Destination>();
source = new Source { Name = null, Data = null };
};
Because of = () => destination = Mapper.Map<Destination>(source);
It should_map_name_to_null = () => destination.Name.ShouldBeNull();
It should_map_array_to_empty = () => destination.Data.ShouldNotBeNull();
}
public class Source
{
public string Name { get; set; }
public string[] Data { get; set; }
}
public class Destination
{
public string Name { get; set; }
public string[] Data { get; set; }
}
As of version 3.1, the should_map_array_to_empty assertion fails because destination.Data is set to null and not an empty array as previously. Is there a way to restore the previous behaviour, preferably globally as opposed to individually per configured map?
The configuration option Mapper.Configuration.AllowNullCollections = false appears to make no difference in this case regardless of the versions of AutoMapper I've tried.

automapper, mapping to an interface

I am using automapper (for .net 3.5). Here is an example to illustrate what I am trying to do:
I want to map an A object to a B object. Class definitions:
class A
{
public I1 MyI { get; set; }
}
class B
{
public I2 MyI { get; set; }
}
interface I1
{
string StringProp1 { get; }
}
interface I2
{
string StringProp1 { get; }
}
class CA : I1
{
public string StringProp1
{
get { return "CA String"; }
}
public string StringProp2 { get; set; }
}
class CB : I2
{
public string StringProp1
{
get { return "CB String"; }
}
public string StringProp2 { get; set; }
}
The mapping code:
A a = new A()
{
MyI = new CA()
};
// Mapper.CreateMap ...?
B b = Mapper.Map<A,B>(a);
I want the resulting object b to be populated with an instance of CB. So automapper needs to know that A maps to B, CA maps to CB, and when creating a B populate it's MyI prop with a CB, how do I specify this mapping?
Something like this:
class Program
{
static void Main(string[] args)
{
Mapper.Initialize(x => x.AddProfile<MappingProfile>());
var a = new A()
{
MyI = new CA()
{
StringProp2 = "sp2"
}
};
var b = Mapper.Map<A, B>(a);
Console.WriteLine("a.MyI.StringProp1: " + a.MyI.StringProp1);
Console.WriteLine("b.MyI.StringProp1: " + b.MyI.StringProp1);
}
}
>= AutoMapper 2.0.0
public class MappingProfile : Profile
{
protected override void Configure()
{
CreateMap<CA, CB>();
CreateMap<CA, I2>().As<CB>();
CreateMap<A, B>();
}
}
AutoMapper 1.1.0.188 (.Net 3.5)
public class MappingProfile : Profile
{
protected override void Configure()
{
CreateMap<CA, CB>();
CreateMap<CA, I2>()
.ConstructUsing(Mapper.Map<CA, CB>)
;
CreateMap<A, B>();
}
}

Can AutoMapper implicitly flatten this mapping?

I am trying to map between two lists of objects. The source type has a complex property of type A; the destination type is a flattened subset of type A plus an additional scalar property that is in the source type.
public class A
{
public int Id { get; set; }
public string Name { get; set; }
}
public class Source
{
public A MyA { get; set; }
public int SomeOtherValue { get; set; }
}
public class Destination
{
public string Name { get; set; }
public int SomeOtherValue { get; set; }
}
If it's not clear, I'd like Source.MyA.Name to map to Destination.Name and Source.SomeOtherValue to map to Destination.SomeOtherValue.
In reality, type A has a dozen or so properties, about which 80% map over to properties of the same name in Destination. I can get things to work if I explicitly spell out the mappings in CreateMap like so:
CreateMap<Source, Destination>()
.ForMember(dest => dest.Name, opt => opt.MapFrom(src => src.MyA.Name));
The downside here is I want to avoid having to add a ForMember line for each of A's properties that need to get copied over to Destination. I was hoping I could do something like:
CreateMap<Source, Destination>()
.ForMember(dest => dest, opt => opt.MapFrom(src => src.MyA));
But if I try the above I get a runtime error when the mapping is registered: "Custom configuration for members is only supported for top-level individual members on a type."
Thanks
create mappings between A and Destination, and Source and Destination, and then use AfterMap() to use first mapping in second
Mapper.CreateMap<A, Destination>();
Mapper.CreateMap<Source, Destination>()
.AfterMap((s, d) => Mapper.Map<A, Destination>(s.MyA, d));
then use it like this:
var res = Mapper.Map<Source, Destination>(new Source { SomeOtherValue = 7, MyA = new A { Id = 1, Name = "SomeName" } });
As a workaround you can use custom type converter with additional property in the destination type to avoid recursion.
[TestFixture]
public class MapComplexType
{
[Test]
public void Map()
{
Mapper.CreateMap<A, Destination>();
Mapper.CreateMap<Source, Destination>().ConvertUsing(new TypeConvertor());
var source = new Source
{
MyA = new A
{
Name = "Name"
},
SomeOtherValue = 5
};
var dest = new Destination();
Mapper.Map(source, dest);
Assert.AreEqual(dest.Name, "Name");
}
}
public class TypeConvertor : ITypeConverter<Source, Destination>
{
public Destination Convert(ResolutionContext context)
{
var destination = (Destination) context.DestinationValue;
if (!((Destination)context.DestinationValue).IsMapped || destination == null)
{
destination = destination ?? new Destination();
destination.IsMapped = true; // To avoid recursion
Mapper.Map((Source)context.SourceValue, destination);
destination.IsMapped = false; // If you want to map the same object few times
}
Mapper.Map(((Source)context.SourceValue).MyA, destination);
return (Destination)context.DestinationValue;
}
}
public class A
{
public int Id { get; set; }
public string Name { get; set; }
}
public class Source
{
public A MyA { get; set; }
public int SomeOtherValue { get; set; }
}
public class Destination
{
public string Name { get; set; }
public int SomeOtherValue { get; set; }
// Used only for mapping purposes
internal bool IsMapped { get; set; }
}
Try this,
Mapper.CreateMap<A, Destination>();
Mapper.CreateMap<Source, Destination>()
.ForMember(destination => destination.Name, options => options.MapFrom(source => Mapper.Map<A, Destination>(source.MyA).Name));
var objSource = new Source { SomeOtherValue = 7, MyA = new A { Id = 1, Name = "SomeName" } };
var result = Mapper.Map<Source, Destination>(objSource);

Automapper map custom collections

Hello. I have a list that looks like this one:
public class PagedList<T> : List<T>
{
public PagedList(IEnumerable<T> collection) : base(collection)
{ }
public int TotalItems { get; set; }
public int CurrentPage { get; set; }
public int PageSize { get; set; }
//some other properties
}
and used in repository for paging
public PagedList<TEntity> GetPaged(int page)
{
var pagedEntities = some_query;
return pagedEntities.AsPagedList(totalResults, page, pageSize);
}
The same PagedList is also used in asp mvc view models for paging.
Is it possible to map this collections using Automapper with all the properties TotalItems/CurrentPage/... ?
PagedList<DbItem> dbItems = _repository.GetPages(page);
var viewItems = new PagedList<SomeItemView>();
Mapper.Map(dbItems , viewItems);
Tahnk You !
This worked for me. Are you looking for something more generic?
public class DbItem
{
public int Id { get; set; }
public string Name { get; set; }
}
public class ViewItem
{
public int Id { get; set; }
public string Name { get; set; }
}
public class PagedList<T>: List<T>
{
public int TotalItems { get; set; }
public int CurrentPage { get; set; }
public int PageSize { get; set; }
}
class Program
{
static void Main(string[] args)
{
MapItems();
}
public static void MapItems()
{
Mapper.CreateMap<DbItem, ViewItem>();
Mapper.CreateMap<PagedList<DbItem>, PagedList<ViewItem>>()
.AfterMap((s, d) => Mapper.Map<List<DbItem>, List<ViewItem>>(s, d));
var dbList = new PagedList<DbItem>
{
new DbItem {Id = 1, Name = "a"},
new DbItem {Id = 2, Name = "b"}
};
dbList.TotalItems = 2;
dbList.CurrentPage = 1;
dbList.PageSize = 10;
var viewList = Mapper.Map<PagedList<DbItem>, PagedList<ViewItem>>(dbList);
Console.WriteLine(viewList.TotalItems);
Console.WriteLine(viewList.CurrentPage);
Console.WriteLine(viewList.PageSize);
Console.WriteLine(viewList[0].Id + " " + viewList[0].Name);
Console.WriteLine(viewList[1].Id + " " + viewList[1].Name);
Console.ReadLine();
}
}
What you need is a custom type converter
public class PagedListConverter<TIn, TOut> : ITypeConverter<IPagedList<TIn>, IPagedList<TOut>>
{
public IPagedList<TOut> Convert(AutoMapper.ResolutionContext context)
{
var source = (IPagedList<TIn>)context.SourceValue;
var mapped = Mapper.Map<IList<TOut>>(source);
return new StaticPagedList<TOut>(mapped, source.GetMetaData());
}
}
Usage:
Mapper.CreateMap<IPagedList<Company>, IPagedList<CompanyViewModel>>().ConvertUsing<PagedListConverter<Company, CompanyViewModel>>();
For those who have faced the similar problem recently, and as an update to NoPyGod's answer, you can achieve the general mapping using ITypeConverter. According to the official documentation:
AutoMapper also supports open generic type converters with any number of generic arguments:
var configuration = new MapperConfiguration(cfg =>
cfg.CreateMap(typeof(Source<>), typeof(Destination<>)).ConvertUsing(typeof(Converter<,>)));
The closed type from Source will be the first generic argument, and the closed type of Destination will be the second argument to close Converter<,>.
So the custom type converter would be:
private class Converter<TSource, TDestination>
: ITypeConverter<PagedList<TSource>, PagedList<TDestination>>
{
public PagedList<TDestination> Convert(
PagedList<TSource> source,
PagedList<TDestination> destination,
ResolutionContext context) =>
new PagedList<TDestination>(
context.Mapper.Map<List<TSource>, List<TDestination>>(source));
/* Additional settings comes here. */
}
And then register it:
this.CreateMap(typeof(PagedList<>), typeof(PagedList<>)).ConvertUsing(typeof(Converter<,>));

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