Develop Reference

Map two classes in runtime using column mapping information provided in a JSON file

I have two Classes like this.
public class InputModel
{
public int studentid { get; set; }
public string studentname { get; set; }
public string studentcity { get; set; }
}
public class OutputModel
{
public int StudentIDColumn { get; set; }
public string StudentNameColumn { get; set; }
public string StudentCityColumn { get; set; }
}
Now the requirement is like this:
I will receive an object of InputModel Class. From this, I need to create an object of OutputModel class.
It's simple if we use a library like AutoMapper. But the problem is, the Column-To-Column Mapping information will be supplied via a Json File like this:
{
"studentid": "StudentIDColumn",
"studentname": "StudentNameColumn",
"studentcity": "StudentCityColumn"
}
Based on the JSON mapping data, I need to Map the columns in runtime and generate the Output class object.
I tried to map the two classes using Automapper. But I am not sure how to do it in runtime using the JSON file.
var MapperConfig = new MapperConfiguration(c =>
c.CreateMap<InputCSVModel, OutputIDMModel>()
.ForMember(dest => dest.StudentIDColumn, act => act.MapFrom(src => src.studentid))
.ForMember(dest => dest.StudentNameColumn, act => act.MapFrom(src => src.studentname))
.ForMember(dest => dest.StudentCityColumn, act => act.MapFrom(src => src.studentcity))
);
var mapper = new Mapper(MapperConfig);
OutputIDMModel outModel = mapper.Map<OutputIDMModel>(inputModel);
I know that it's might be possible to do this with Reflection. But is there any better approach ?

I was able to read the JSOn file and pass the strings in the automapper config like this.
var MapperConfig = new MapperConfiguration(c =>
c.CreateMap<InputModel, OutputModel>()
.ForMember("StudentIDColumn", opt => opt.MapFrom("studentid"))
.ForMember("StudentNameColumn", opt => opt.MapFrom("studentname"))
.ForMember("StudentCityColumn", opt => opt.MapFrom("studentcity"))
);

Automapper: mapping between different types

Assuming I have a class structure like
public class Entity
{
public List<EntityChild> Children { get; set; }
}
public class EntityChild
{
public int Id { get; set; }
public string Name { get; set; }
}
and I want to map Entity using AutoMapper to a class EntityDto and reverse.
public class EntityDto
{
public List<int> EntityChildrenIds { get; set; }
}
I don't have any clue how to configure AutoMapper to map this properly in both directions. I know my Name property will be null when mapping from EntityDto to Entity but this would not be a problem.

For mapping both ways this configuration works for me:
var mapperConfiguration = new MapperConfiguration(cfg =>
{
cfg.CreateMap<Entity, EntityDto>()
.ForMember(dest => dest.EntityChildrenIds, opt => opt.MapFrom(src => src.Children))
.ReverseMap();
cfg.CreateMap<EntityChild, int>().ConvertUsing(child => child.Id);
cfg.CreateMap<int, EntityChild>().ConvertUsing(id => new EntityChild
{
Id = id
});
});
Since the properties have different names we need to configure that mapping.
Then just add general mappings from EntityChild to int and back again and we're done.

if .ReverseMap(), as mentioned by #knoop, didn't work maybe you should map it manually:
CreateMap<Entity, EntityDto>(MemberList.None)
.ForMember(dest => dest.EntityChildrenIds, opts => opts.MapFrom(src => MapChildrenIds(src.Children)));
CreateMap<EntityDto, Entity>(MemberList.None)
.ForMember(dest => dest.Children, opts => opts.MapFrom(src => MapChildren(src.EntityChildrenIds)));
private List<EntityChild> MapChildren(List<int> entityChildrenIds)
{
var listEntityChild = new List<EntityChild>();
foreach (var childId in entityChildrenIds)
listEntityChild.Add(new EntityChild { Id = childId });
return listEntityChild;
}
private List<int> MapChildrenIds(List<EntityChild> children)
{
return children.Select(x => x.Id).ToList();
}

How to provide additional parameter to Mapper's Map method?

I'm trying to map one list to another, but not everything I want is in the source object. Let me explain:
These are my two objects:
public class SourceItem
{
public int Id { get; set;}
public string Name { get; set;}
}
public class TargetItem
{
public int TargetId { get; set;}
public string TargetName { get; set;}
public int Foo { get; set; }
}
This is how I configure my Mapper:
public class MyProfile : Profile
{
public MyProfile()
{
CreateMap<SourceItem, TargetItem>()
.ForMember(dest => dest.TargetId, opt => opt.MapFrom(src => src.Id))
.ForMember(dest => dest.TargetName, opt => opt.MapFrom(src => src.Name));
}
}
When I do this...
var targets = Mapper.Map<List<SourceItem>, List<TargetItem>>(sourceItems);
...the targets list's objects will have Foo set to 0. Obviously. What I'm trying to do is to also initialize Foo (with the parameter). Like this:
fooParameter = 321;
List<TargetItem> targets = Mapper.Map<List<SourceItem>, List<TargetItem>>(sourceItems);
foreach(var target in targets)
{
target.Foo = fooParameter;
}
Is it possible, to do it using Mapper?
Thanks in advance!

You can't do exactly what you want, but you can get pretty close by specifying mapping options when you call Map.
fooParameter = 321;
var targets = Mapper.Map<List<SourceItem>, List<TargetItem>>(sourceItems, opt =>
opt.AfterMap(
(src, dest) => {
foreach (var d in dest)
{
d.Foo = fooParameter;
}
})
);

Map just one field with Automapper

I'm using Automapper to define a mapping configuration between some objects. I need to retrieve single mapped values for the destination based on the configuration.
Let's say I have a domain object
class Person
{
public string FirstName { get; set; }
public string LastName { get; set; }
}
and a corresponding DTO
class PersonDTO
{
public string FullName { get; set; }
}
and a mapping
Mapper.CreateMap<Person, PersonDTO>()
.ForMember(
dest => dest.FullName,
opts => opts.MapFrom(src => src.FirstName + " " + src.LastName));
I'd like a method like Mapper.MapField<PersonDTO>(person, x => x.FullName) that returns just one mapped value (that would get assigned to the specified field in a full mapping). Is there any way I can do this without mapping the whole object and extracting the value from the result?

First create a resolver and then use the resolve using method in your mapper call.
public class PersonNameResolver : ValueResolver<Person, PersonDTO>
{
protected override PersonDTO ResolveCore(Person source)
{
return new PersonDTO
{
FirstName = source.FirstName,
LastName = source.LastName
};
}
}
Once this is created, use the following in your mapper call.
Mapper.CreateMap<Person, PersonDTO>()
.ForMember(
dest => dest.Name,
opts => opts.ResolveUsing<PersonNameResolver>().FromMember(o => o))

Need help with AutoMapper

I have two classes that looks as follows:
public class Rule
{
public int Id { get; set; }
public RuleGroup RuleGroup { get; set; }
}
public class RuleGroup
{
public int Id { get; set; }
public List<Rule> RuleList { get; set; }
}
A RuleGroup has a list of rules. My AutoMapper settings are as follows:
Mapper.CreateMap<RuleRecord, FirstSolar.Mes.Core.Entities.Recipe.Rule>()
.ForMember(destination => destination.RuleGroup, source => source.Ignore())
.ForMember(destination => destination.Id, source => source.MapFrom(item => item.RuleId));
Mapper.CreateMap<IList<RuleRecord>, IList<FirstSolar.Mes.Core.Entities.Recipe.Rule>>();
Mapper.CreateMap<RuleGroupRecord, FirstSolar.Mes.Core.Entities.Recipe.RuleGroup>()
.ForMember(destination => destination.Id, source => source.MapFrom(item => item.RuleGroupId));
Mapper.CreateMap<IList<RuleGroupRecord>, IList<FirstSolar.Mes.Core.Entities.Recipe.RuleGroup>>();
When I attempt to map a RuleGroupRecord (LinqToSQL object) to RuleGroup (DTO), AutoMapper says I need to add a mapping for RuleGroup.RuleList. I'm wondering why because I defined how to map a single RuleRecord and a List.
If I have to, how would I do it?

Simply add (I hope I got the syntax right, but you should see what I'm hinting at):
.ForMember(destination => destination.RuleList, source => source.MapFrom(item => item.Rules));
to the second mapping. While you handled the general mapping for RuleRecord to Rule in the first mapping, you didn't tell automapper to map the specific property RuleGroup.RuleList.