CODEWITHSUNDEEP
c#automapper
Adam Levitt
Adam Levitt

Reputation: 10476

AutoMapper Writing Null On Target Field When Source Field Does Not Exist

I have the following objects:

public class DomainStudent {
    public long Id { get; set; }
    public string AdvisorId { get; set; }
}

public class ApiStudent {
    public long Id { get; set; }
    public long AdvisorName { get; set; }
}

When I run the following mapping:

ApiStudent api = new ApiStudent();
api.Id = 123;
api.AdvisorName = "Homer Simpson";

DomainStudent existing = service.load(api.Id); // 123
// at this point existing.AdvisorId = 555

existing = Mapper.Map<ApiStudent, DomainStudent>(api);
// at this point existing.AdvisorId = null

How can I configure AutoMapper such that when the property AdvisorId is missing from the source object, so that it does not get overwritten to null?

Upvotes: 1

Views: 2178

Answers (1)

peflorencio
peflorencio

Reputation: 2482

You must change the Map() call to:

Mapper.Map(api, existing);

and then configure the mapping to:

 Mapper.CreateMap<ApiStudent, DomainStudent>()
            .ForMember(dest => dest.AdvisorId, opt => opt.Ignore());

Upvotes: 3

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