Error when creating mappings with AutoMapper - entity-framework

Question

I'm trying to map objects with AutoMapper. I've created the HTTP POST controller method, which should create the new Part object to database. It should add data to both entities, Part and PartAvailabilites. Database is already existing and is scaffolded by EF Core. The error I'm receiving is:
AutoMapper created this type map for you, but your types cannot be mapped using the current configuration Part -> PartDto (Destination member list)PartManagement.Entities.Part -> PartManagement.Dto.PartDto (Unmapped properties:Balance)"
Does anyone know what could be the problem with this mapping? I tried to do the mapping in several ways but none of them is working.
Here is my mapping:
CreateMap<PartDto, PartEntity>()
.ForMember(dest => dest.FkPartAvailability,
opts => opts.MapFrom(src => new PartAvailabilities
{
Balance = src.Balance
}));
Example JSON request:
{
"name": "testPart",
"catalogNumber": 12345,
"balance": 10
}
Here are my entity classes:
public class Part
{
public long Id { get; set; }
public int PartNumber { get; set; }
public string Name { get; set; }
public PartAvailabilities FkPartAvailability { get; set; }
}
public class PartAvailabilities
{
public PartAvailabilities()
{
Parts = new HashSet<Part>();
}
public long Id { get; set; }
public decimal Balance { get; set; }
public ICollection<Part> Parts { get; set; }
}
public class PartDto
{
public string Name { get; set; }
public int PartNumber { get; set; }
public decimal Balance { get; set; }
}
This is Create method in the ManagementService class:
public async Task<PartDto> Create(PartDto request)
{
var part = _mapper.Map<PartDto, PartEntity>(request);
var createdPart = partRepository.Add(part);
await partRepository.UnitOfWork.SaveChangesAsync();
return _mapper.Map<PartDto>(createdPart);
}
And here is HttpPost method from controller:
[HttpPost]
public async Task<IActionResult> Part_Create([FromBody] PartDto request)
{
PartDto createdPart;
try
{
if (request != null)
{
createdPart = await _partManagementService.Create(request);
return Ok(request);
}
}
catch(Exception ex)
{
return BadRequest(ex.Message);
}
return Ok(new string[] { "Part created" });
}

Answer 1

The message is trying to tell you that there is no map between Part and PartDto. AM will create a map for you, but that map is not valid, because PartDto.Balance cannot be mapped. So you have to create the map and tell AM how to map Balance. Things might be easier to understand if you set CreateMissingTypeMaps to false.