Updating complex objects in database with AutoMapper - how to ignore nested objects for one time map?

Question

Let me explain a bit. Here are my classes:

// ClassOne
int ID
string Name
ClassTwo ClassTwoExample

// ClassTwo
int ID
string Name
ClassThree ClassThreeExample
ClassFour ClassFourExample

// ClassThree
int ID
string Name

// ClassFour
int ID
string Name

So you get the general gist of it. ClassOne is my main / parent class and holds ClassTwo. ClassTwo holds a ton of information and references to even more classes. ClassThree and ClassFour are just reference classes which I do not need to modify.

My goal is to update the properties in ClassOne and the basic properties in ClassTwo (ignoring ClassThree and ClassFour). However, when I go to update using AutoMapper (_mapper.Map(..,..)), it's also trying to map ClassThree and ClassFour which end up being null and the database tries saving them.

Here is my mapping method:

// Mapping snippet
function (ClassOne model) {
    var oldClassOne = _repos.GetClassOne(model.ID);
    _mapper.Map(model, oldClassOne)
    await _repos.SaveAllAsync();
}

Is there anywhere in that piece of code where I can tell AutoMapper to ignore specific properties and just specifically map what I want it to?

Have you tried what the post suggested from the link [https://stackoverflow.com/a/4988159/2410655](https://stackoverflow.com/a/4988159/2410655)? — David Liang, May 30 '18 at 19:05

score 1 · Accepted Answer · answered May 30 '18 at 20:58

Initialize your Mapper like this

public class AutoMapperConfig
{
    public static void RegisterMappings()
    {
        Mapper.Initialize(m =>
        {
            m.CreateMap<ClassOne, ClassOne>().ForMember(d => d.ClassTwoExample.ClassThreeExample, s => s.Ignore())
                                             .ForMember(d => d.ClassTwoExample.ClassFourExample, s => s.Ignore());
        });
    }

}

Updating complex objects in database with AutoMapper - how to ignore nested objects for one time map?

1 Answers1