activestep/Step.Model/DTOModels/MaintenanceModels/DTOMaintenanceNoteModel.cs

using Step.Model.DatabaseModels;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Step.Model.DTOModels.MaintenanceModels
{
    public class DTONewMaintenanceNoteModel
    {
        [Required]
        public string Message { get; set; }
    }

    public class DTOMaintenanceNoteModel : DTONewMaintenanceNoteModel
    {
        public int Id { get; set; }

        public DateTime DateTime { get; set; }
        
        public DTOMessageUserModel User { get; set; }
        
        public static explicit operator DTOMaintenanceNoteModel(MaintenanceNoteModel note)
        {
            DTOMessageUserModel user = note.User != null ? (DTOMessageUserModel)note.User : null;
            return new DTOMaintenanceNoteModel()
            {
                Id  = note.Id,
                DateTime = note.DateTime,
                Message = note.Message,
                User = user
            };
        }
    }
}