具有未知值的无效枚举的自动驾驶器

发布于 2025-01-29 04:51:53 字数 1371 浏览 1 评论 0原文

我在源侧有一个无效的枚举属性，并以值0而不是null获取此属性。但是0不是枚举中的代表值，因此使用ContractingEnumpapping引发了无法映射枚举的异常。有没有办法将其映射到null时，每当该值在源枚举中没有表示时？阻止此运行时错误的某种方法？

public class SomeSourceDto
{
    public SomeSourceEnum? SomeEnum { get; set; }
}

public class SomeDestinationDto
{
    public SomeDestinationEnum? SomeEnum { get; set; }
}

public enum SomeSourceEnum
{
    First = 1
}

public enum SomeDestinationEnum
{
    First = 1
}

映射配置：

CreateMap<SomeSourceDto, SomeDestinationDto>();
CreateMap<SomeSourceEnum, SomeDestinationEnum>().ConvertUsingEnumMapping(opt => opt.MapByName());

映射：

var someSourceDto = new SomeSourceDto { SomeEnum = 0 };
Mapper.Map<SomeDestinationDto>(someSourceDto);

异常：

automapper.automappermpappingexception
错误映射类型。
...
目标成员：
someenum

我目前的解决方法是在地图之前应用此方法：

someSourceDto.SomeEnum = someSourceDto.SomeEnum == 0 ? null : someSourceDto.SomeEnum;

有更好的方法吗？当我在地图上制作枚举类型时，我无法使用ContructusEnumpapping。

问题在于，这可能会发生在每个ENUM属性中，因此我有运行时错误ATM的很大风险，因为我无法控制数据的源端。

原文

I have a nullable enum property on the source side and get this property with value 0 instead of NULL.
But 0 is not a represented value in the enum so AutoMapper with ConvertUsingEnumMapping throws an exception that the enum can not be mapped. Is there a way to map it to NULL whenever the value is not represented in the source enum? Some way to prevent this runtime error?

public class SomeSourceDto
{
    public SomeSourceEnum? SomeEnum { get; set; }
}

public class SomeDestinationDto
{
    public SomeDestinationEnum? SomeEnum { get; set; }
}

public enum SomeSourceEnum
{
    First = 1
}

public enum SomeDestinationEnum
{
    First = 1
}

Mapping configuration:

CreateMap<SomeSourceDto, SomeDestinationDto>();
CreateMap<SomeSourceEnum, SomeDestinationEnum>().ConvertUsingEnumMapping(opt => opt.MapByName());

Mapping:

var someSourceDto = new SomeSourceDto { SomeEnum = 0 };
Mapper.Map<SomeDestinationDto>(someSourceDto);

Exception:

AutoMapper.AutoMapperMappingException
Error mapping types.
...
Destination Member:
SomeEnum

My current workaround is to apply this before the map:

someSourceDto.SomeEnum = someSourceDto.SomeEnum == 0 ? null : someSourceDto.SomeEnum;

Is there a better way? I can't use ConvertUsingEnumMapping when I make the enum types in the map nullable.

The problem is that this can happen for every enum property so I'm at big risk of runtime errors atm because I have no control over the source side of the data.

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荒岛晴空 2025-02-05 04:51:53

您可以这样处理：

CreateMap<SomeSourceDto, SomeDestinationDto>()
    .ForMember(
        dst => dst.SomeEnum,
        opt => opt.MapFrom(
            src => Enum.IsDefined(typeof(SomeDestinationEnum), src.SomeEnum) 
            ? src.SomeEnum 
            : null));

您可以将其重写为扩展方法，以便您可以更轻松地将其用于其他DTO

You can work it around like this:

CreateMap<SomeSourceDto, SomeDestinationDto>()
    .ForMember(
        dst => dst.SomeEnum,
        opt => opt.MapFrom(
            src => Enum.IsDefined(typeof(SomeDestinationEnum), src.SomeEnum) 
            ? src.SomeEnum 
            : null));

You can rewrite this to an extension method so you can use it more easily for other DTO's

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