嵌套映射的AutoMapper扁平化要求提供自定义解析(AutoMapper flattening

2019-08-02 14:37发布

我有点新的AutoMapper,想要映射POCO十岁上下的对象也许是一个更复杂的DTO,后者试图成为的表示谷歌图书API的卷资源:

Book.cs

public class Book
{
    public string Isbn10 { get; set; }
    public string Isbn13 { get; set; }
    public string Title { get; set; }
    public string Author { get; set; }
    public string Publisher { get; set; }
    public DateTime Publication { get; set; }
    public int Pages { get; set; }
    public string Description { get; set; }
    public bool InStock { get; set; }
}

BookDto.cs

public class BookDto
{
    public string Kind { get; set; }
    public string Id { get; set; }
    public VolumeInfo VolumeInfo { get; set; }
}

public class VolumeInfo
{
    public string Title { get; set; }
    public List<string> Authors { get; set; }
    public string Publisher { get; set; }
    public string PublishedDate { get; set; }
    public string Description { get; set; }
    public int PageCount { get; set; }
    public List<IndustryIdentifier> IndustryIdentifiers { get; set; }
}

public class IndustryIdentifier
{
    public string Type { get; set; }
    public string Identifier { get; set; }
}

因此,根据文档 ,我们可以简单地压平嵌套类型:

AutoMapperConfigurator.cs

public static class AutoMapperConfigurator
{
    public static void Configure()
    {
        Mapper.CreateMap<Book, BookDto>()
            .ForMember(dto => dto.Id, options => options.Ignore())
            .ForMember(dto => dto.Kind, options => options.Ignore())
            .ForMember(dto => dto.VolumeInfo.Title, options => options.MapFrom(book => book.Title))
            .ForMember(dto => dto.VolumeInfo.Authors, options => options.MapFrom(book => book.Author.ToArray()))
            .ForMember(dto => dto.VolumeInfo.Publisher, options => options.MapFrom(book => book.Publisher))
            .ForMember(dto => dto.VolumeInfo.PublishedDate, options => options.MapFrom(book => book.Publication))
            .ForMember(dto => dto.VolumeInfo.Description, options => options.MapFrom(book => book.Description))
            .ForMember(dto => dto.VolumeInfo.PageCount, options => options.MapFrom(book => book.Pages))
            ;
    }
}

但在运行时不幸Mapper.AssertConfigurationIsValid()测试,我发现了以下错误:

System.ArgumentException:表达式“DTO => dto.VolumeInfo.Title”必须解析顶级成员,没有任何子对象的属性。 在子类型或代替AfterMap选项使用自定义解析。 参数名:lambdaExpression

所以,现在下面这个建议与AfterMap尝试:

public static class AutoMapperConfigurator
{
    public static void Configure()
    {
        Mapper.CreateMap<Book, BookDto>()
            .ForMember(dto => dto.Id, options => options.Ignore())
            .ForMember(dto => dto.Kind, options => options.Ignore())
            .AfterMap((book, bookDto) => bookDto.VolumeInfo = new VolumeInfo 
                { 
                    Title = book.Title,
                    Authors = new List<string>(){ book.Author },
                    Publisher = book.Publisher,
                    PublishedDate = book.Publication.ToShortDateString(),
                    Description = book.Description,
                    PageCount = book.Pages
                });
    }
}

当再次运行测试,我现在得到这个消息:

未映射成员被发现。 查看下面的类型和成员。 添加自定义映射表达式,忽略,添加自定义解析,或修改源/目标类型预订 - > BookDto(目的地成员列表)Dotnet.Samples.AutoMapper.Book - > Dotnet.Samples.AutoMapper.BookDto(目的地成员列表) VolumeInfo

我应该创建嵌套类之间的附加映射? 任何指导将衷心感谢,感谢很多提前。

Answer 1:

我已经做了类似的东西使用.ForMember与该VolumnInfo映射内部映射之前:

public static class AutoMapperConfigurator
{
    public static void Configure()
    {
        Mapper.CreateMap<Book, VolumeInfo>()
            .ForMember(dto => dto.Authors, options => options.MapFrom(book => book.Author.Split(',')))
            .ForMember(dto => dto.PublishedDate, options => options.MapFrom(book => book.Publication))
            .ForMember(dto => dto.PageCount, options => options.MapFrom(book => book.Pages))
            .ForMember(dto => dto.IndustryIdentifiers, options => options.Ignore());

        Mapper.CreateMap<Book, BookDto>()
            .ForMember(dto => dto.Id, options => options.Ignore())
            .ForMember(dto => dto.Kind, options => options.Ignore())
            .ForMember(dto => dto.VolumeInfo, options => options.MapFrom(book => Mapper.Map<Book, VolumeInfo>(book)));
    }
}

这里有一对夫妇的单元测试验证的功能:

[TestFixture]
public class MappingTests
{
    [Test]
    public void AutoMapper_Configuration_IsValid()
    {
        AutoMapperConfigurator.Configure();
        Mapper.AssertConfigurationIsValid();
    }

    [Test]
    public void AutoMapper_MapsAsExpected()
    {
        AutoMapperConfigurator.Configure();
        Mapper.AssertConfigurationIsValid();

        var book = new Book
            {
                Author = "Castle,Rocks",
                Description = "Awesome TV",
                InStock = true,
                Isbn10 = "0123456789",
                Isbn13 = "0123456789012",
                Pages = 321321,
                Publication = new DateTime(2012, 11, 01),
                Publisher = "Unknown",
                Title = "Why I Rock"
            };

        var dto = Mapper.Map<Book, BookDto>(book);

        Assert.That(dto.Id, Is.Null);
        Assert.That(dto.Kind, Is.Null);
        Assert.That(dto.VolumeInfo, Is.Not.Null);
        Assert.That(dto.VolumeInfo.Authors, Is.Not.Null);
        Assert.That(dto.VolumeInfo.Authors.Count, Is.EqualTo(2));
        Assert.That(dto.VolumeInfo.Authors[0], Is.EqualTo("Castle"));
        Assert.That(dto.VolumeInfo.Authors[1], Is.EqualTo("Rocks"));
        Assert.That(dto.VolumeInfo.Description, Is.EqualTo("Awesome TV"));
        Assert.That(dto.VolumeInfo.IndustryIdentifiers, Is.Null);
        Assert.That(dto.VolumeInfo.PageCount, Is.EqualTo(321321));
        Assert.That(dto.VolumeInfo.PublishedDate, Is.EqualTo(new DateTime(2012, 11, 01).ToString()));
        Assert.That(dto.VolumeInfo.Publisher, Is.EqualTo("Unknown"));
        Assert.That(dto.VolumeInfo.Title, Is.EqualTo("Why I Rock"));
    }
}


文章来源: AutoMapper flattening of nested mappings asks for a custom resolver