Allow mapping of dynamic types using AutoMapper or similar?

LiamB picture LiamB · Oct 15, 2011 · Viewed 39.8k times · Source

I've started to use https://github.com/robconery/massive for a project, I wonder if there is any mapping tool that allows support for Dynamic to static type mapping?

I've used AutoMapper previously, does AutoMapper support this?

I am aware of the DynamicMap function from AutoMapper, however I believe this function is for running maps without creating the Map first. In my example below it does not work.

dynamic curUser = users.GetSingleUser(UserID);   
var retUser = Mapper.DynamicMap<UserModel>(curUser);
users.GetSingleUser(UserID); // returns a dynamic object

Answer

nemesv picture nemesv · Oct 15, 2011

AutoMapper 4.2.0 now supports Dynamic/expando/dictionary mapping

With this feature you can map to your expando objects to static types:

dynamic CurUser = _users.GetSingleUser(UserID);   
var config = new MapperConfiguration(cfg => { });
var mapper = config.CreateMapper();

var retUser = mapper.Map<UserModel>(CurUser);

Old versions of AutoMapper do not support this (Massive internally uses ExpandoObject which doesn't provide which properties it has), and you are right Mapper.DynamicMap is for mapping without creating mapping configuration.

Actually it's not hard to write yourself a mapper if you just want simple mapping:

public static class DynamicToStatic
{
    public static T ToStatic<T>(object expando)
    {
        var entity = Activator.CreateInstance<T>();

        //ExpandoObject implements dictionary
        var properties = expando as IDictionary<string, object>; 

        if (properties == null)
            return entity;

        foreach (var entry in properties)
        {
            var propertyInfo = entity.GetType().GetProperty(entry.Key);
            if(propertyInfo!=null)
                propertyInfo.SetValue(entity, entry.Value, null);
        }
        return entity;
    }
}

dynamic CurUser = _users.GetSingleUser(UserID);   
var retUser = DynamicToStatic.ToStatic<UserModel>(CurUser);