I have tried created a custom type converter using automapper, but I cannot get to work – or even compile for that matter.

Here is my custom converter:

public class WorkPlanToWorkingTimeListConverter : ITypeConverter<TPWorkPlanDTO, IEnumerable<WorkingTime>>
{
    public IEnumerable<WorkingTime> Convert(TPWorkPlanDTO source, IEnumerable<WorkingTime> destination, ResolutionContext context)
    {
        if (source == null)
        {
            return Enumerable.Empty<WorkingTime>(); 
        }

        return (IEnumerable<WorkingTime>)source.Weeks.SelectMany(week => week.Days.SelectMany(day => day.Shifts));
    }
}

I am trying to wire it up like this:

  CreateMap<TPWorkPlanDTO, List<WorkingTime>>()
   .ConvertUsing<WorkPlanToWorkingTimeConverter>();

But I get this error:

The type ‘Mapping.Converter.WorkPlanToWorkingTimeListConverter’ cannot be used as type parameter ‘TTypeConverter’ in the generic type or method ‘IMappingExpressionBase<TPWorkPlanDTO, List, IMappingExpression<TPWorkPlanDTO, List>>.ConvertUsing()’. There is no implicit reference conversion from ‘Mapping.Converter.WorkPlanToWorkingTimeListConverter’ to ‘AutoMapper.ITypeConverter<TPWorkPlanDTO, System.Collections.Generic.List<Models.WorkingTime>>’.

I have tried some of the overloads of ConvertUsing() taking types, but I just can not make it compile.

Underneath I have attached my DTO and model I need to map:

namespace Mapping.DTO;

public class TPWorkPlanDTO
{
    public class TPWorkingTimeDTO
    {
        public int worktime_id { get; set; }
        public DateTime start_time { get; set; }
        public DateTime end_time { get; set; }
    }
    public class TPWorkPlanDay
    {
        public IEnumerable<TPWorkingTimeDTO> Shifts { get; set; }
    }
    public class TPWorkPlanWeek
    {
        public IEnumerable<TPWorkPlanDay> Days { get; set; }
    }
    public IEnumerable<TPWorkPlanWeek> Weeks { get; set; }
}

namespace Models;
public class WorkingTime
{
    public int Id { get; set; }
    public DateTime StartTime { get; set; }
    public DateTime EndTime { get; set; }
}