Automapper reflection error with Json.Net JObject

Question

I'm getting a reflection error when using AutoMapper with a json.net JObject

public class Source
{
    public string Key { get; set; }
    public JObject Value { get; set; }
}

Here is the target

public class Target
{
    public string Key { get; set; }
    public JObject Value { get; set; }
}

Here is the mapping

public class SourceTargetMapping
{
    public static void IntializeMapping()
    {
        Mapper.CreateMap<Target, Source>()
            .ForMember(g => g.Value, op => op.ResolveUsing(s => s.Value));

        Mapper.CreateMap<Source, Target>()
            .ForMember(s => s.Value, op => op.ResolveUsing(g => g.Value));
    }

}

public static class SourceTargetMappingExtensions
{
    public static Source ToDomain(this Target repoItem)
    {
        var result = Mapper.Map<Target, Source>(repoItem);
        return result;
    }

    public static Target ToRepo(this Source domainItem)
    {
        var result = Mapper.Map<Source, Target>(domainItem);
        return result;
    }

    public static List<Source> ToDomain(this ICollection<Target> repoCollection)
    {
        return Mapper.Map<ICollection<Target>, List<Source>>(repoCollection);
    }

    public static List<Target> ToRepo(this ICollection<Source> domainCollection)
    {
        return Mapper.Map<ICollection<Source>, List<Target>>(domainCollection);
    }

}

Here is the (NUnit) unit test (the ones with non empty values fail, empty values pass)

[TestFixture]
public class AutoMappingTest
{
  [SetUp]
  public void SetUp()
  {
    SourceTargetMapping.IntializeMapping();
    Mapper.AssertConfigurationIsValid();
  }

  [TestCase("State", "{\"State\":\"TX\"}", "Should handle normal value")]
  [TestCase("State", @"{""State"":""TX""}", "double quoted quotes")]
  [TestCase("State", "", "empty json")]
  [TestCase("State", null, "null json")]
  public void ShouldMapFromSourceToTarget(string key, string value, string description)
  {
    //arrange
    JObject jObject = (!string.IsNullOrEmpty(value)) ? JObject.Parse(value) : new JObject();
    var source = new Source() {Key = key, Value = jObject};

    //act
    var repo = source.ToRepo();

    Assert.IsNotNull(repo);
    Assert.AreEqual(key, repo.Key);
  }

And here is the exception:

AutoMapper.AutoMapperMappingException : 

Mapping types:
JObject -> JObject
Newtonsoft.Json.Linq.JObject -> Newtonsoft.Json.Linq.JObject

Destination path:
Target.Value

Source value:
{
  "State": "TX"
}
  ----> System.Reflection.TargetException : Object does not match target type.
at IsolationChamber.SourceTargetMappingExtensions.ToRepo(Source domainItem) in SourceTargetMapping.cs: line 62
at IsolationChamberTest.AutoMappingTest.ShouldMapFromSourceToTarget(String key, String value, String description) in AutoMapperSiteSettingTest.cs: line 35
--TargetException
at System.Reflection.RuntimeMethodInfo.CheckConsistency(Object target)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, Object[] index)
at AutoMapper.Mappers.DictionaryMapper.Map(ResolutionContext context, IMappingEngineRunner mapper)
at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context)

Any help is appreciated. Thank you.

You posted the code of SiteSettingMapping but your test using SourceTargetMapping, is it a typo? And can you post the code for SourceTargetMappingExtensions.ToRepo? — nemesv
– nemesv, Commented May 13, 2012 at 15:55
I posted an update to the mapping code in the question. thanks — What Would Be Cool
– What Would Be Cool, Commented May 13, 2012 at 16:10

jool · Accepted Answer · 2013-10-30 21:01:05Z

8

I had the same issue, just add an explicit mapping JObject -> JObject which makes a clone.

Mapper.CreateMap<JObject, JObject>().ConvertUsing(value =>
{
    if (value == null)
        return null;

    return new JObject(value);
});

answered Oct 30, 2013 at 21:01

jool

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Comments

What Would Be Cool · Accepted Answer · 2012-05-16 17:55:58Z

0

It turns out I was not doing the mapping correctly. I created a custom type converter per AutoMapper's documentation and then it worked.

answered May 16, 2012 at 17:55

What Would Be Cool

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