如何用AutoMapper将StatusSqlModel的Id转换为UploadStatus枚举

给定以下C#类定义：

public class StatusSqlModel
{
    public int Id { get; set; }
    
    public string Name { get; set; }
}

public enum UploadStatus
{
    Created,
    InProgress,
    Succeeded,
    Failed,
    Cancelled
}

需要实现映射关系：1→Created、2→InProgress、3→Succeeded、4→Failed、5→Cancelled，将StatusSqlModel的Id字段转换为UploadStatus枚举。

方法一：直接使用ConvertUsing定义转换逻辑 #

创建AutoMapper配置Profile，直接指定从StatusSqlModel到UploadStatus的转换规则：

public class StatusMappingProfile : Profile
{
    public StatusMappingProfile()
    {
        CreateMap<StatusSqlModel, UploadStatus>()
            .ConvertUsing(model => model.Id switch
            {
                1 => UploadStatus.Created,
                2 => UploadStatus.InProgress,
                3 => UploadStatus.Succeeded,
                4 => UploadStatus.Failed,
                5 => UploadStatus.Cancelled,
                _ => throw new ArgumentOutOfRangeException(nameof(model.Id), "传入的状态ID不在有效范围内")
            });
    }
}

初始化AutoMapper并执行映射：

// 初始化配置
var mapperConfig = new MapperConfiguration(cfg =>
{
    cfg.AddProfile<StatusMappingProfile>();
});
var mapper = mapperConfig.CreateMapper();

// 执行映射
var sqlStatus = new StatusSqlModel { Id = 3 };
UploadStatus result = mapper.Map<UploadStatus>(sqlStatus);
// result 为 UploadStatus.Succeeded

方法二：映射到包含枚举的目标类 #

如果需要将StatusSqlModel映射到包含UploadStatus属性的ViewModel（如StatusViewModel），可通过ForMember指定单个属性的转换逻辑：

public class StatusViewModel
{
    public UploadStatus Status { get; set; }
    // 其他业务属性...
}

// 在Profile中配置映射
public class StatusMappingProfile : Profile
{
    public StatusMappingProfile()
    {
        CreateMap<StatusSqlModel, StatusViewModel>()
            .ForMember(dest => dest.Status, opt => opt.MapFrom(src => src.Id switch
            {
                1 => UploadStatus.Created,
                2 => UploadStatus.InProgress,
                3 => UploadStatus.Succeeded,
                4 => UploadStatus.Failed,
                5 => UploadStatus.Cancelled,
                _ => throw new ArgumentOutOfRangeException(nameof(src.Id), "无效的状态ID")
            }));
    }
}

方法三：使用自定义ValueResolver（适合复杂逻辑） #

若转换逻辑需要复用或包含更复杂的业务判断，可创建自定义解析器：

public class StatusIdToEnumResolver : IValueResolver<StatusSqlModel, object, UploadStatus>
{
    public UploadStatus Resolve(StatusSqlModel source, object destination, UploadStatus destMember, ResolutionContext context)
    {
        return source.Id switch
        {
            1 => UploadStatus.Created,
            2 => UploadStatus.InProgress,
            3 => UploadStatus.Succeeded,
            4 => UploadStatus.Failed,
            5 => UploadStatus.Cancelled,
            _ => throw new ArgumentOutOfRangeException(nameof(source.Id), "状态ID无效")
        };
    }
}

// 在Profile中使用解析器
public class StatusMappingProfile : Profile
{
    public StatusMappingProfile()
    {
        CreateMap<StatusSqlModel, StatusViewModel>()
            .ForMember(dest => dest.Status, opt => opt.MapFrom<StatusIdToEnumResolver>());
    }
}

注意事项 #

• 确保已通过NuGet安装AutoMapper包：Install-Package AutoMapper 或使用.NET CLI命令：dotnet add package AutoMapper
• 无效ID的处理：示例中抛出异常，你可根据业务需求改为返回默认枚举值（如UploadStatus.Created）

内容的提问来源于stack exchange，提问作者SimonD