AutoMapper配置文件：展平dto以进行映射

Question

I have a Main class that has a nested class. I have used this successfully to map using Mapper class

public class Main
{
    public string Name { get; set; }
    public List<QuantityLocation> NC { get; set; }
}

public class NestedClass
{
    public decimal B { get; set; }
    public string A { get; set; }
}

public class Flattened
{
    public string Name { get; set; }

    public string A { get; set; }
    public decimal B { get; set; }
}

Mapping done using the Mapper class as below.

    Mapper.CreateMap<NestedClass, Flattened>();
    Mapper.CreateMap<Main, Flattened>();
    Mapper.CreateMap<Main, List<Flattened>>()
        .ConvertUsing(i =>
                i.NC.Select(
                    flat =>
                    {
                        var flatList = Mapper.Map<Flattened>(i);
                        Mapper.Map(flat, flatList);
                        return flatList;
                    }).ToList());

Now when I moved this mapping to my Profile class, I had to change the lines above to this below:

CreateMap<NestedClass, Flattened>();
CreateMap<Main, Flattened>();
CreateMap<Main, List<Flattened>>()
    .ConvertUsing(i =>
            i.NC.Select(
                flat =>
                {
                    var flatList = Mapper.Map<Flattened>(i);
                    Mapper.Map(flat, flatList);
                    return flatList;
                }).ToList());

The problem I am facing is how to convert these two lines below in the snippet above.

               var flatList = Mapper.Map<Flattened>(i);
                Mapper.Map(flat, flatList);

you see I am injecting the Mapper.Engine to the constructor of my controllers. Earlier I was just using the Static Mapper class which used to get called in my global.asax. Now I get an error like the one below.

Missing type map configuration or unsupported mapping.

Mapping types: Main -> List`1 MyProj.Main -> System.Collections.Generic.List`1[[MyProj.Flattened, MyProj, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]

Destination path: List`1

Source value: MyProj.Main

Answer 1

The proper way to do is to use a custom type converter , in which you inject the mapping engine itself. And use ConstructServicesUsing in your profile declaration.

Assuming you use some of IoC container, and you have registered in it the mapping engine, and the custom type converter, inside the converter you will use engine.Map instead the static Mapper.