将DTO映射到Entity AutoMapper时如何解决创建循环依赖关系

Question

I have a database hierarchy like: Between Worksheet and Device is a one-to-one relationship. When I'm trying to map the WorksheetDto to Worksheet AutoMapper makes a circular dependency through Worksheet and Device.

I've searched a lot after solution and I've found, that I have to ignore the Device's Worksheet reference. (I mean Device.Worksheet)

Entities and DTOs:

public class Worksheet : EntityBase
    {
        public virtual Device Device { get; set; }
    }

public class WorksheetDto : EntityBaseDto
    {
        public virtual DeviceDto Device { get; set; }
    }

public class Device : EntityBase
    {
        public virtual Worksheet Worksheet { get; set; }
    }

public class DeviceDto : EntityBaseDto
    {
        public virtual WorksheetDto Worksheet { get; set; }
    }

AutoMapper config:

var config = new MapperConfiguration(cfg =>
            {

                cfg.CreateMap<Device, DeviceDto>();
                    .ForMember(w => w.Worksheet, map => map.Ignore())
                    .PreserveReferences()
                    .ReverseMap();
            });

When I use it like this, nothing happens and got the following error:

System.InvalidOperationException: 'Multiplicity constraint violated. The role 'Worksheet_Device_Target' of the relationship 'RMDApp.DataLayer.Worksheet_Device' has multiplicity 1 or 0..1.'

So the summary is that I can see the circular dependency after all when I'm debugging. So EF can't upload the Worksheet because of the error it provides.

Answer 1

worksheet and device has one to one mapping , but choose whether you want to load device when you want to get worksheet or vice versa.

keep virtual only in one place, it will not try to load and will not create circular dependencies