Mapping Lists using Automapper
asp.net MvcAutomapperasp.net Mvc Problem Overview
I have the classes:
public class Person{ /* Props here */ }
public class PersonViewModel { /* Props here */ }
Then the list:
List<Person> people = new List<Person>();
List<PersonViewModel> peopleVM = Mapper
.MapList<Person, PersonViewModel>(people); //Problem here.
What is the correct way to do this?
asp.net Mvc Solutions
Solution 1 - asp.net Mvc
Mapper.CreateMap<Person, PersonViewModel>();
peopleVM = Mapper.Map<List<Person>, List<PersonViewModel>>(people);
Mapper.AssertConfigurationIsValid();
From Getting Started:
> How do I use AutoMapper?
>
> First, you need both a source and destination type to work with. The destination type's design can be influenced by the layer in which it lives, but AutoMapper works best as long as the names of the members match up to the source type's members. If you have a source member called "FirstName", this will automatically be mapped to a destination member with the name "FirstName". AutoMapper also supports Flattening, which can get rid of all those pesky null reference exceptions you might encounter along the way.
>
>Once you have your types, and a reference to AutoMapper, you can create a map for the two types.
>
> Mapper.CreateMap
Solution 2 - asp.net Mvc
Another Solution
List<Person> people = new List<Person>();
List<PersonViewModel> peopelVM;
peopelVM = people.Select(Mapper.Map<Person, PersonViewModel>);
And in the Automapper config
Mapper.CreateMap<Person, PersonViewModel>();
Solution 3 - asp.net Mvc
If you're using IQueryable
lists here (from EF or NH, for example) you can use the AutoMapper.IQueryableExtensions
methods, Project()
and To()
.
This is my first time with AutoMapper, but I'm succeeding by creating a map for just the model:
Mapper.CreateMap<Person, PersonViewModel>();
Mapper.AssertConfigurationIsValid();
And then using the IQueryableExtension
methods Project()
and To()
:
using AutoMapper.QueryableExtensions;
...
IQueryable<Person> people = new List<Person>().AsQueryable(); //actually from ORM
IQueryable<PersonViewModel> peopleVM = people.Project().To<PersonViewModel>();
Solution 4 - asp.net Mvc
In core 1.1 this extension might work:
public static List<TDestination> MapList<TSource, TDestination>(this IMapper mapper, List<TSource> source)
{
return source.Select(x => mapper.Map<TDestination>(x)).ToList();
}
Solution 5 - asp.net Mvc
Another Solution
mapper.Map<IEnumerable<PersonViewModel>>(people);
Solution 6 - asp.net Mvc
You could create an extension method to do something like this using existing mappings for individual items:
public static class AutoMapperExtensions
{
public static List<TDestination> MapList<TSource, TDestination>(this IMapper mapper, List<TSource> source)
{
return mapper.Map<List<TDestination>>(source);
}
}
Usage:
List<PersonViewModel> peopleVM = _mapper.MapList<PersonViewModel>(people);