Question

我有AspNetUser实体：

public partial class AspNetUser
{
    public string Id { get; set; }

    [Required]
    [StringLength(256)]
    [Index(IsClustered = false, IsUnique = true)]
    public string UserName { get; set; }
    ....

接口：

public interface IProfile
{
    string FirstName { get; set; }
    string LastName { get; set; }
    string Nickname { get; set; }
}

public interface IMembershipEntity
{
    string AspNetUserId { get; set; }
    AspNetUser AspNetUser { get; set; }
}

还有2个实体，它们每个都以FK链接到AspNetUser（都实现IProfile和IMembershipEntity）：

public partial class Driver : IMembershipEntity, IProfile
{

    #region IProfile
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Nickname { get; set; }
    #endregion

    #region IMembershipEntity
    public string AspNetUserId { get; set; }
    [ForeignKey("AspNetUserId")]
    public virtual AspNetUser AspNetUser { get; set; }
    #endregion

   ... driver fields


public class User : BaseEntity, IMembershipEntity, IProfile
{
    #region IMembershipEntity
    public string AspNetUserId { get; set; }
    public virtual AspNetUser AspNetUser { get; set; }
    #endregion

    #region IProfile
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Nickname { get; set; }
    #endregion

    .... user fields
}

现在我需要一个需要从AspNetUser获取FirstName / LastName的方法，像这样：

        var element = (from i in db.AspNetUsers
                    select new UserElementDomain()
                    {
                        UserId = i.Id,
                        CompanyName = i.Company.Name,
                        FirstName = (get FirstName here),
                        LastName = (get LastName here),
                        RoleName = i.AspNetRoles.FirstOrDefault().Name,
                        SMSnumber = i.SMSnumber,
                        UserName = i.UserName,
                        .....
                    }).FirstOrDefault();

该怎么做？我可以向AspNetUser添加2个属性，例如：

    public virtual User User { get; set; }
    public virtual Driver Driver { get; set; }

但是怎么说，它应该是一个或零个链接，而不创建UserId / DriverId

即使有它，我也必须编写如下代码：

FirstName = (i.User!=null)? i.User.FirstName : ((i.Driver!=null)?i.Driver.FirstName : String.Empty)

并且我不喜欢这段代码，因为当我再添加一个实体时，我必须查看所有代码并再添加一个条件。如何正确做？可能是使用接口/继承吗？

Answer 1

我以前看过重复的代码，但是很少看到重复的数据结构。

根据您当前的代码，如果User.FirstName =“ A”＆Driver.FirstName =“ B”，则结果仅为“ A”。如果您有一个名为“ Employee”的新实体，并且您不使用当前样式对它进行硬编码，谁知道哪个名称将是3个实体中的真实名字？

您当前的代码可以简化为：

i.User?.FirstName ?? i.Driver?.FirstName ?? i.Whatever?.FirstName ?? String.Empty

但这是您要管理的真实数据吗？

我给您另外两个选择：

向根实体添加属性，在您的情况下为AspNetUser：

public class AspNetUser
{
....
public string FirstName { get; set; }
public string LastName { get; set; }
public string Nickname { get; set; }
....
}

管理1个实体中的常用配置文件

public class AspNetUser
{
....
public virtual AspNetUserProfile AspNetUserProfile { get; set; }
}
public class AspNetUserProfile
{
[Key]
public string Id { get; set; }

public string FirstName { get; set; }
public string LastName { get; set; }
public string Nickname { get; set; }
....
[ForeignKey("Id")]
public virtual AspNetUser AspNetUser { get; set; }
}

然后在您的代码中：

   db.AspNetUsers.Select(i => new UserElementDomain()
                {
                    UserId = i.Id,
                    CompanyName = i.Company.Name,
                    FirstName = i.AspNetUserProfile?.FirstName,
                    LastName = i.AspNetUserProfile?.LastName,
                    RoleName = i.AspNetRoles.FirstOrDefault().Name,
                    SMSnumber = i.SMSnumber,
                    UserName = i.UserName,
                    .....
                })

如果驱动程序/用户/ Empolyee要获取名字，只需使用：

Empolyee.AspNetUser.AspNetUserProfile?.FirstName

实体框架代码优先和链接的实体

1 个答案: