AutoMapper 捕获并忽略 NullReferenceException

Question

也许这是设计使然，但我们最初并不希望自动映射器捕获并忽略映射中的所有 NullReferenceException。我们主要使用 MapFrom 并有时创建复杂的表达式。我们希望这些映射在出现任何异常（甚至是 NullReferenceException）时失败，但我们无法让 AutoMapper 做到这一点。有没有办法让自动映射器不忽略所有这些异常，而不必为每种情况编写自定义值解析器？这对我们来说意味着大量额外的代码，事实上，如果不首先使用 automapper，代码可能会更少。

这些是我们期望全部通过的测试：

[TestFixture]
public class Tests
{
    [SetUp]
    public void Setup() { Mapper.Reset(); }

    [Test]
    public void ShouldThrowMappingExceptionUsingMapFromExpression()
    {
        Mapper.CreateMap<Source, Destination>()
            .ForMember(d => d.DestinationMember, o => o.MapFrom(s => s.SourceMember.SourceProperty))
            ;

        Assert.Throws<AutoMapperMappingException>(() => Mapper.Map<Source, Destination>(new Source()));
    }

    [Test]
    public void ShouldThrowMappingExceptionUsingResolveUsingExpression()
    {
        Mapper.CreateMap<Source, Destination>()
            .ForMember(d => d.DestinationMember, o => o.ResolveUsing(s => s.SourceMember.SourceProperty))
            ;

        Assert.Throws<AutoMapperMappingException>(() => Mapper.Map<Source, Destination>(new Source()));
    }

    [Test]
    public void ShouldThrowMappingExceptionUsingResolverInstance()
    {
        Mapper.CreateMap<Source, Destination>()
            .ForMember(d => d.DestinationMember, o => o.ResolveUsing(new TestValueResolver()).FromMember(s => s.SourceMember))
            ;

        Assert.Throws<AutoMapperMappingException>(() => Mapper.Map<Source, Destination>(new Source()));
    }

    [Test]
    public void ShouldThrowMappingExceptionUsingResolverType()
    {
        Mapper.CreateMap<Source, Destination>()
            .ForMember(d => d.DestinationMember, o => o.ResolveUsing<TestValueResolver>().FromMember(s => s.SourceMember))
            ;

        Assert.Throws<AutoMapperMappingException>(() => Mapper.Map<Source, Destination>(new Source()));
    }

}

public class Destination
{
    public string DestinationMember { get; set; }
}

public class Source
{
    public SourceChild SourceMember { get; set; }
}

public class SourceChild
{
    public string SourceProperty { get; set; }
}

public class TestValueResolver : ValueResolver<SourceChild, string>
{
    protected override string ResolveCore(SourceChild source)
    {
        return source.SourceProperty;
    }
}

Answer 1

此行为现​​已在 AutoMapper 中更改！ :-)

https://github.com/AutoMapper/AutoMapper/issues/122