将Automapper v5.0的代码重写为v4.0

Question

Automapper v4.0在方法中使用非常直接，有人能帮助为v5.0重写它吗（特别是Mapper代码）：

    public IEnumerable<NotificationDto> GetNewNotifications()
    {
        var userId = User.Identity.GetUserId();
        var notifications = _context.UserNotifications
            .Where(un => un.UserId == userId && !un.IsRead)
            .Select(un => un.Notification)
            .Include(n => n.Gig.Artist)
            .ToList();
        Mapper.CreateMap<ApplicationUser, UserDto>();
        Mapper.CreateMap<Gig, GigDto>();
        Mapper.CreateMap<Notification, NotificationDto>();
        return notifications.Select(Mapper.Map<Notification, NotificationDto>);
    }

更新：EF Core似乎没有投影AutoMapper所映射的内容：

return notifications.Select(Mapper.Map<Notification, NotificationDto>);

但我确实在Postman中得到了以下代码的结果：

        return notifications.Select(n => new NotificationDto()
        {
            DateTime = n.DateTime,
            Gig = new GigDto()
            {
                Artist = new UserDto()
                {
                    Id = n.Gig.Artist.Id,
                    Name = n.Gig.Artist.Name
                },
                DateTime = n.Gig.DateTime,
                Id = n.Gig.Id,
                IsCancelled = n.Gig.IsCancelled,
                Venue = n.Gig.Venue
            },
            OriginalVenue = n.OriginalVenue,
            OriginalDateTime = n.OriginalDateTime,
            Type = n.Type
        });

Answer 1

如果您想继续使用静态实例，唯一的变化是在映射器初始化中：

Mapper.Initialize(cfg =>
{
    cfg.CreateMap<ApplicationUser, UserDto>();
    cfg.CreateMap<Gig, GigDto>();
    cfg.CreateMap<Notification, NotificationDto>();
});

此外，您应该在每个AppDomain（例如启动时的某个地方）只运行一次此代码，而不是每次调用GetNewNotifications。