Automapper 在 .net 核心中的反向映射中不起作用

Question

I am using .Net core with Entity Framework. Below is my code

View Model

public class EmployeeVm
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string ContactNo { get; set; }
        public string Email { get; set; }
        public DateTime JoiningDate { get; set; }
        public int BranchId { get; set; }
        public int DepartmentId { get; set; }
    }

POCO Class

public class employee
    {
        [Key]
        public int id { get; set; } 
        public string name { get; set; }
        public string contact_no { get; set; }
        public string email { get; set; }
        public DateTime joining_date { get; set; }
        public int branch_id { get; set; }
        public int department_id { get; set; }      
    }

Automapper configuration from Startup class

public void ConfigureServices(IServiceCollection services)
        {
            var mappingConfig = new MapperConfiguration(mc =>
            {
                mc.AddProfile(new MappingProfile());
            });

            IMapper mapper = mappingConfig.CreateMapper();
            services.AddSingleton(mapper);
        }

Mapping Profile class

public class MappingProfile : Profile
    {
        public MappingProfile()
        {
            CreateMap<employee, EmployeeVm>();
            CreateMap<EmployeeVm, employee>();
        }
    }

When I am trying to map View Model properties to POCO class properties using below code it is working fine.

//Here I am using constructor injection
private readonly IMapper _mapper;
public EmployeeBl(IMapper mapper)
{
    _mapper = mapper;
}

_mapper.Map<employee>(employeeVm)

But when I am trying to map POCO class ( employee ) properties to View Module ( EmployeeVm ) properties then some properties are not mapping as it contains underscore in POCO class

Here is the response of postman

{
    "id": 4,
    "name": "test",
    "contactNo": null,
    "email": "test@gmail.com",
    "joiningDate": "0001-01-01T00:00:00",
    "branchId": 0,
    "departmentId": 0,
}

From above response I am expecting to map contactNo, joiningDate, branchId and departmentId properties with respective value.

Answer 1

https://docs.automapper.org/en/stable/Configuration.html#naming-conventions

You can set the source and destination naming conventions

var configuration = new MapperConfiguration(cfg => {
  cfg.SourceMemberNamingConvention = new LowerUnderscoreNamingConvention();
  cfg.DestinationMemberNamingConvention = new PascalCaseNamingConvention();
});

This will map the following properties to each other: property_name -> PropertyName

You can also set this at a per profile level

public class OrganizationProfile : Profile
{
  public OrganizationProfile()
  {
    SourceMemberNamingConvention = new LowerUnderscoreNamingConvention();
    DestinationMemberNamingConvention = new PascalCaseNamingConvention();
    //Put your CreateMap... Etc.. here
  }
}

Answer 2

AutoMapper doesn't map snake_case to PascalCase automatically. You have to configure naming conventions as described here: https://docs.automapper.org/en/v9.0.0/Configuration.html#naming-conventions

Or map the properties one at at a time.

However, assuming your "POCO class" is something you need to store in a database using some persistance framework, a better approach would be to configure your persistance tool with knowledge about the snake_cased column names in the database, and let your C# objects conform to C# naming conventions, which dictate that property names should be PascalCase. This means you can name the properties identically and allow the default AutoMapper config to map your objects.

Answer 3

you can also map the prop which has diff name apart of configuration

Mapper.CreateMap<employee, EmployeeVm>()
    .ForMember(dest => dest.JoiningDate, opt => opt.MapFrom(src => joining_date ));