Dictionary <string,string> map to an object using Automapper

Question

I have a class like

public User class
{
 public string Name{get;set;}
 public string Age{get;set;
}

With a dictionary like

Dictionary<string,string> data= new Dictionary<string,string>(); 
data.Add("Name","Rusi");
data.Add("Age","23");

User user= new User();

Now i want to map User object to this dictionary using Automapper. Automapper maps properties of objects but in my case there is a dictionary and object.

How can this be mapped?

Answer 1

AutoMapper maps between properties of objects and is not supposed to operate in such scenarios. In this case you need Reflection magic. You could cheat by an intermediate serialization:

var data = new Dictionary<string, string>();
data.Add("Name", "Rusi");
data.Add("Age", "23");
var serializer = new JavaScriptSerializer();
var user = serializer.Deserialize<User>(serializer.Serialize(data));

And if you insist on using AutoMapper you could for example do something along the lines of:

Mapper
    .CreateMap<Dictionary<string, string>, User>()
    .ConvertUsing(x =>
    {
        var serializer = new JavaScriptSerializer();
        return serializer.Deserialize<User>(serializer.Serialize(x));
    });

and then:

var data = new Dictionary<string, string>();
data.Add("Name", "Rusi");
data.Add("Age", "23");
var user = Mapper.Map<Dictionary<string, string>, User>(data);

If you need to handle more complex object hierarchies with sub-objects you must ask yourself the following question: Is Dictionary<string, string> the correct data structure to use in this case?

Answer 2

This thread is a bit old, but nowadays there's how to do it on automapper without any configuration, as stated at official documentation:

AutoMapper can map to/from dynamic objects without any explicit configuration (...) Similarly you can map straight from Dictionary to objects, AutoMapper will line up the keys with property names.

Update:

The following code shows a working sample (with unit tests).

void Test()
{
    var mapper = new MapperConfiguration(cfg => { }).CreateMapper();
    var dictionary = new Dictionary<string, object>()
    {
        { "Id", 1 },
        { "Description", "test" }
    };

    var product = mapper.Map<Product>(dictionary);

    Assert.IsNotNull(product);
    Assert.AreEqual(product.Id, 1);
    Assert.AreEqual(product.Description, "test");
}

class Product
{
    public int Id { get; set; }
    public string Description { get; set; }
}

Answer 3

With the current version of AutoMapper:

public class MyConfig
{
    public string Foo { get; set; }
    public int Bar { get; set; }
}
var config = new MapperConfiguration(cfg => {});
var mapper = config.CreateMapper();

var source = new Dictionary<string, object>
{
    ["Foo"] = "Hello",
    ["Bar"] = 123
};
var obj = mapper.Map<MyConfig>(source);
obj.Foo == "Hello"; // true

Answer 4

AutoMapper is quite a flexible solution. You could probably achieve this using a custom mapping profile, e.g.:

public class UserMappingProfile : Profile
{
  // Props
  public override string ProfileName { get { return "UserMappingProfile"; } }

  // Methods
  public override void Configure()
  {
    CreateMap<User, Dictionary<string, string>>().ConvertUsing<DictionaryTypeConverter>();
    base.Configure();
  }

  // Types
  internal class DictionaryTypeConverter : ITypeConverter<User, Dictionary<string, string>>
  {
    public User Convert(ResolutionContext context)
    {
      var dict = context.SourceValue as Dictionary<string, string>;
      if (dict == null)
        return null;

      return new User() { Name = dict["Name"], Age = dict["Age"] };
    }
  }
}

With this, I can create a custom instance of a mapper:

var config = new Configuration(new TypeMapFactory(), MapperRegistry.AllMappers());
config.AddProfile<UserMappingProfile>();

config.AssertConfigurationIsValid();

var mapper = new MappingEngine(config);

Which I could probably do:

var dict = new Dictionary<string, string> { { "Name", "Matt" }, { "Age", "27" } };
var user = mapper.Map<User, Dictionary<string, string>>(dict);