禁用 AutoMapper 内置枚举映射器

Question

Is it possible to disable the built-in mapper for enums in AutoMapper, or replace it with one that always throws an exception?

I find the built in mapper to be highly unreliable as it will try it's best to map an input to any enum you give it which increases the risk of introducing, difficult to trace, bugs in your code.

I'd much rather have it fail with an exception telling me that I'm missing a mapper/converter than have it just work and then several steps down the call stack the code fails because the value isn't right in the current context.

Answer 1

From what you write I can think of a few options:

1. If you have an enum property on an object, you can ignore it explicitly by using:

    CreateMap<Foo, Bar>().ForMember(dest => dest.EnumProperty, opt => opt.Ignore());

2. If you create mappings for the properties you want to map and leave out the enum properties you can use:

    CreateMap<Foo, Bar>().ForMember(...).ForAllOtherMembers(opt => opt.Ignore())

3. If you want to replace the mapping between to enum types you can overwrite it with:

    Mapper.CreateMap<EnumSrc,EnumDst>().ConvertUsing(value => { throw new Exception(); });

Answer 2

Based on the comment from Lucian i added the following code to my configuration:

services.AddAutoMapper(config =>
{
  var enumMapper = config.Mappers.Single(m => m is AutoMapper.Mappers.EnumToEnumMapper);
  config.Mappers.Remove(enumMapper);
}, typeof(Startup));

This removes the default EnumToEnum mapper and gives me the exception when no mapping is configured.