CODEWITHSUNDEEP
c#automapper
Dennis
Dennis

Reputation: 37780

Ignore properties when mapping derived type instance

Here's the simple hierarchy:

abstract class Base
{
    public int Id { get; set; }
}

class Derived : Base
{
    public string Name { get; set; }
}

I need to clone Derived instances, but I want to skip Id values. So, I'm configuring mapper this way:

        Mapper
            .CreateMap<Base, Base>()
            .Include<Derived, Derived>()
            .ForMember(_ => _.Id, expression => expression.Ignore());

        var original = new Derived
        {
            Id = 1,
            Name = "John"
        };

        var clone = Mapper.Map<Derived>(original);

        Console.WriteLine(clone.Id == 0); // writes 'False'

Regardless of ForMember call, the value of Id is mapped.

This configuration:

        Mapper
            .CreateMap<Derived, Derived>()
            .ForMember(_ => _.Id, expression => expression.Ignore());

works as expected, but this is not an option, because it needs to set ForMember for each derived type.

Automapper version is 2.2.1. What am I doing wrong?

Upvotes: 0

Views: 990

Answers (1)

polkduran
polkduran

Reputation: 2551

Have you tried to Ignore also the Id property on the base class mapping?

Mapper
    .CreateMap<Base, Base>()
    .ForMember(_ => _.Id, expression => expression.Ignore())
    .Include<Derived, Derived>()
    .ForMember(_ => _.Id, expression => expression.Ignore());

[...]convention has a higher priority that Ignored properties in the base class mappings[...]

https://github.com/AutoMapper/AutoMapper/wiki/Mapping-inheritance

Upvotes: 1

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