Automapper 映射不一致

Question

我有这门课下课。 student, studentrequest(Dto) , mapping profile 和 apicontroller。

我不知道为什么它映射到空值。

public class Student : BaseEntity, IAuditableEntity, IDeletableEntity
{
    [Required]
    public string StudentId { get; set; }
    [Required]
    public string NameKH { get; set; }
    [Required]
    public string NameEN { get; set; }
    public string PhoneNumber { get; set; }
    public string MotherNameKH { get; set; }
    public string MotherNameEN { get; set; }
    public string FatherNameKH { get; set; }
    public string FatherNameEN { get; set; }
    public string MotherPhoneNumber { get; set; }
    public string FatherPhoneNumber { get; set; }
    [Required]
    public string CurrentAddress { get; set; }
    [Required]
    public string Nationality { get; set; }
    [Required]
    public string Ethnicity { get; set; }
    [Required]
    public DateTime DateOfBirth { get; set; }
    [Required]
    public string PlaceOfBirth { get; set; }
    public string Notes { get; set; }
    [Required]
    public string CreatedBy { get; set; }
    [Required]
    public DateTime CreatedOn { get; set; }
    public string LastModifiedBy { get; set; }
    public DateTime? LastModifiedOn { get; set; }
    public bool IsDeleted { get; set; }
    public DateTime? DeletedOn { get; set; }
}

和 DTO

public class StudentRequest
{
    [Required]
    public string StudentId { get; set; }
    [Required]
    public string NameKH { get; set; }
    [Required]
    public string NameEN { get; set; }
    public string PhoneNumber { get; set; }
    public string MotherNameKH { get; set; }
    public string MotherNameEN { get; set; }
    public string FatherNameKH { get; set; }
    public string FatherNameEN { get; set; }
    public string MotherPhoneNumber { get; set; }
    public string FatherPhoneNumber { get; set; }
    [Required]
    public string CurrentAddress { get; set; }
    [Required]
    public string Nationality { get; set; }
    [Required]
    public string Ethnicity { get; set; }
    [Required]
    public DateTime DateOfBirth { get; set; }
    [Required]
    public string PlaceOfBirth { get; set; }
    public string Notes { get; set; }
}

映射配置文件

 CreateMap<StudentRequest, Student>()

我的更新 API 控制器

[HttpPut("{id}")]
public async Task<ActionResult> Update(int id, StudentRequest studentRequest)
{
    var student = await _context.Students.SingleOrDefaultAsync(x => x.IsDeleted != true && x.Id == id);
    if (student == null) return NotFound(new ApiResponse(404, "Student Not Found"));

    student = _mapper.Map<StudentRequest, Student>(studentRequest);
    student.LastModifiedBy = GetCurrentUserName();
    student.LastModifiedOn = DateTime.Now;

    try
    {
        _context.Students.Add(student);
        await _context.SaveChangesAsync(GetCurrentUserName(), GenerateIPAddress());
        return Ok(new ApiResponse(200, "Succesfully Added Student"));
    }
    catch (Exception ex)
    {
        Log.Error(ex.Message);
        return BadRequest(new ApiResponse(400, "Error Adding Student"));
    }
}

这条线student = _mapper.Map<StudentRequest, Student>(studentRequest);

第一个学生已有CreatedBy、CreatedOn、数据。

但映射后，student.CreatedBy = null;

我不知道这个行为映射有什么问题。

Answer 1

studentMapped = _mapper.Map<StudentRequest, Student>(studentRequest); 
student = studentMapped;

studentRequest 没有CreatedBy 属性。所以studentMapped.CreatedBy 将为空。您将其设置为学生。
我认为这段代码可能会有所帮助：

_mapper.Map<StudentRequest, Student>(studentRequest,student);