[英]AutoMapper mapping from multiple properties to complex objects fails with ReverseMap and custom value resolver
[英]Automapper flattening multiple complex objects using custom mapping
因此,除了常规的DTO到业务映射器之外,我还有其他东西,并且我试图以最少的映射代码来映射它们。
设定
public class Target {
public string propA { get; set; }
public string propB { get; set; }
public string propC { get; set; }
public string propD { get; set; }
public string propE { get; set; }
public List<KeyValuePair> Tokens { get; set; }
}
public class Source {
public SomeClass SomeClass { get; set; }
public AnotherClass AnotherClass { get; set; }
}
public class SomeClass {
public string propA { get; set; }
public string propB { get; set; }
public string propDifferent { get; set; }
public List<KeyValuePair> Tokens { get; set; }
}
public class AnotherClass {
public string propC { get; set; }
public string propD { get; set; }
public List<KeyValuePair> Tokens { get; set; }
}
映射器配置
Mapper.CreateMap<SomeClass, Target>()
.ForMember(dest => dest.propE, opt => opt.MapFrom(src => src.propDifferent));
Mapper.CreateMap<AnotherClass, Target>();
Mapper.CreateMap<Source, Target>()
.ForMember(dest => dest, opt => opt.MapFrom(src => src.SomeClass))
.ForMember(dest => dest, opt => opt.MapFrom(src => src.AnotherClass));
这样做抛出
错误:AutoMapper.AutoMapperConfigurationException:仅类型的顶级单个成员支持成员的自定义配置。
而且我还需要获取AnotherClass.Tokens
和SomeClass.Tokens
并将其添加到Target.Tokens
。
我知道我可以使用.ConvertUsing
但是随后我必须为每个属性定义映射,而我失去了基于约定的映射来匹配属性的优点。
除了实现.ConvertUsing
或手动映射每个属性之外,还有其他方法可以实现吗?
如果不通过Automapper,它是通过EmitMapper可行? 我想添加到令牌列表可能可以通过EmitMapper的PostProcessing
。
更新
经过一番黑客攻击后,我找到了一种方法:
public static IMappingExpression<TSource, TDestination> FlattenNested<TSource, TNestedSource, TDestination>(this IMappingExpression<TSource, TDestination> expression)
{
var sourceType = typeof(TNestedSource);
var destinationType = typeof(TDestination);
var sourceProperties = sourceType.GetProperties().ToDictionary(x => x.Name.ToLowerInvariant());
var childPropName = typeof (TSource).GetProperties().First(x => x.PropertyType == sourceType).Name;
var mappableProperties = destinationType.GetProperties()
.Where(p => sourceProperties.ContainsKey(p.Name.ToLowerInvariant()) &&
sourceProperties[p.Name.ToLowerInvariant()].PropertyType ==
p.PropertyType)
.Select(p => new {DestProperty = p.Name, SrcProperty = sourceProperties[p.Name.ToLowerInvariant()].Name});
foreach (var property in mappableProperties)
{
expression.ForMember(property.DestProperty,
opt => opt.MapFrom(src => src.GetPropertyValue(childPropName).GetPropertyValue(property.SrcProperty)));
}
return expression;
}
注意:我执行Name.ToLowerInvariant()
以便能够匹配AccountID
> AccountId
等。
用法
AutoMapper.Mapper.CreateMap<Source, Target>()
.FlattenNested<Source, SomeClass, Target>()
.FlattenNested<Source, AnotherClass, Target>()
.ForMember(dest => dest.propE, opt => opt.MapFrom(src => src.propDifferent));
我在IMappingExpression
中发现了一些其他属性, IMappingExpression
属性也许可以使用和清除。 找到我会更新。
这就是我解决类似问题的方法:
public static IMappingExpression<TSource, TDestination> FlattenNested<TSource, TNestedSource, TDestination>(
this IMappingExpression<TSource, TDestination> expression,
Expression<Func<TSource, TNestedSource>> nestedSelector,
IMappingExpression<TNestedSource, TDestination> nestedMappingExpression)
{
var dstProperties = typeof(TDestination).GetProperties().Select(p => p.Name);
var flattenedMappings = nestedMappingExpression.TypeMap.GetPropertyMaps()
.Where(pm => pm.IsMapped() && !pm.IsIgnored())
.ToDictionary(pm => pm.DestinationProperty.Name,
pm => Expression.Lambda(
Expression.MakeMemberAccess(nestedSelector.Body, pm.SourceMember),
nestedSelector.Parameters[0]));
foreach (var property in dstProperties)
{
if (!flattenedMappings.ContainsKey(property))
continue;
expression.ForMember(property, opt => opt.MapFrom((dynamic)flattenedMappings[property]));
}
return expression;
}
用法
public class Customer
{
public string FirstName { get; set; }
public string LastName { get; set; }
public Address Address { get; set; }
}
public class Address
{
public string City { get; set; }
public string Street { get; set; }
}
public class CustomerDto
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string City { get; set; }
public string Street { get; set; }
}
public class CustomerProfile : Profile
{
protected override void Configure()
{
var nestedMap = CreateMap<Address, CustomerDto>()
.IgnoreAllNonExisting();
CreateMap<Customer, CustomerDto>()
.FlattenNested(s => s.Address, nestedMap);
}
}
[TestFixture]
public class CustomerProfileTests
{
[Test]
public void Test()
{
Mapper.Initialize(c => c.AddProfile<CustomerProfile>());
Mapper.AssertConfigurationIsValid();
}
}
IgnoreAllNonExisting()
在这里找到。
尽管它不是通用解决方案,但对于简单的案例来说就足够了。
优点是:
RecognizePrefixes
东西。 您要使用BeforeMap实例化该对象:
更新:
Mapper.CreateMap<Source, Target>()
.BeforeMap(( Source, Target) => {
Source.SomeClass = new SomeClass();
Source.AnotherClass = new AnotherClass();
})
.AfterMap(( Source, Target) => {
Target.SomeClass = Mapper.Map<AnotherClass, Target>(Target);
Target.AnotherClass = Mapper.Map<SomeClass, Target>(Target);
})
这样,您就可以在映射单个对象属性之前先映射父对象。
我想我已经迷失了您的基类名称,但是您可以调用mapper.Map属性来映射对象。
更新2:
基于此代码:
Mapper.CreateMap<Source, Target>()
.ForMember(dest => **dest**, opt => opt.MapFrom(src => src.SomeClass))
.ForMember(dest => **dest**, opt => opt.MapFrom(src => src.AnotherClass));
目的地正在尝试解析对象。 如果只想解析那些对象的属性,那么我建议您指定它们。
Mapper.CreateMap<Source, Target>()
.ForMember(dest => dest.propA, opt => opt.MapFrom(src => src.SomeClass.propA
.ForMember(dest => dest.propB, opt => opt.MapFrom(src => src.SomeClass.propB
.ForMember(dest => dest.propC, opt => opt.MapFrom(src => src.AnotherClass.propC
.ForMember(dest => dest.propD, opt => opt.MapFrom(src => src.AnotherClass.propD
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