Automapper实体框架外键为null

Question

我正在尝试使用实体框架更新数据库，我使用automapper将我的实体映射到viewmodels，并以相同的方式将其映射回来：

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([FromJson] MyCVViewModel model)
{
    var userId = User.Identity.GetUserId();
    //find the cv
    CV cv = repository.FindCV(model.CVId);

    //auto mapper mapping
    Mapper.CreateMap<MyCVViewModel, CV>();
    Mapper.CreateMap<MyCompanyViewModel, Company>();
    cv = Mapper.Map<MyCVViewModel, CV>(model, cv);

    //edit
    repository.EditCV(cv);
}

当我将其映射回来时，公司实体内的外键CVid变为0，我认为在映射过程中丢失了一些东西，你如何映射外键？

这是我的视图模型和实体：

查看型号：

public class MyCVViewModel
{
    public int CVId { get; set; }

    [Required]
    [StringLength(100, ErrorMessage = "Title cannot exceed 100 characters.")]
    [Display(Name = "Title")]
    public string Title { get; set; }
    [Required]
    [StringLength(1000, ErrorMessage = "Statment cannot exceed 1000 characters.")]
    [Display(Name = "Statement")]
    public string Statement { get; set; }

    public bool Reference { get; set; }

    public List<MyCompanyViewModel> Companies { get; set; }
}

public class MyCompanyViewModel
{
    [Required]
    [StringLength(100, ErrorMessage = "Company Name cannot exceed 100 characters.")]
    [Display(Name = "Company Name")]
    public string CompanyName { get; set; }
    [Required]
    [StringLength(100, ErrorMessage = "Job Title cannot exceed 100 characters.")]
    [Display(Name = "Job Title")]
    public string JobTitle { get; set; }
    [Required]
    [DataType(DataType.Date)]
    [Display(Name = "Start Date")]
    public DateTime StartDate { get; set; }
    [Required]
    [DataType(DataType.Date)]
    [Display(Name = "End Date")]
    public DateTime EndDate { get; set; }
    [Required]
    [StringLength(1000, ErrorMessage = "Job Description cannot exceed 1000 characters.")]
    [Display(Name = "Job Description")]
    public string Description { get; set; }
}

实体：

public class CV
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int CVId { get; set; }
    public string Title { get; set; }
    public string Statement { get; set; }
    public bool Reference { get; set; }

    public virtual ICollection<Company> Companies { get; set; }
}

public class Company
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int CompanyId { get; set; }

    public string CompanyName { get; set; }
    public string JobTitle { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime EndDate { get; set; }
    public string Description { get; set; }

    public virtual CV CV { get; set; }
    public int CVId { get; set; }
}

这是我尝试更新时的错误消息：

操作失败：无法更改关系，因为一个或多个外键属性不可为空。对关系进行更改时，相关的外键属性将设置为空值。

我知道问题所在，但不知道如何告诉automapper保留外键值

Answer 1

MyCompanyViewModel类不包含CVId属性的定义，因此默认情况下，Automapper不知道应该将值注入Company的位置CVId财产。public class MyCompanyViewModel { public int CVId { get; set; } // Other properties } 。只需定义它：

CompanyViewModel

然后为每个@for (int i = 0; i < Model.Companies.Count; i++) { // ... @Html.HiddenFor(m => Model.Companies[i].CVId) // ... } 添加相应的隐藏输入字段到视图中：

{{1}}

你很高兴去！