實體類型需要定義一個主鍵

Question

我有 3 個從基類Person繼承的模型類（ Customer, Manager, Technician ）。 Id鍵在Person基類中定義。

當我嘗試為Customer類生成控制器時，會出現一個錯誤，表明實體類型 customer 必須有一個主鍵。

這是我的Person類：

public class Person
{
    [Key]
    public int Id { get; }
    [EmailAddress]
    public string? Email { get; set; }
    public int? Cin { get; set; }
    public string? Address { get; set; }
    [Required]
    public string Name { get; set; }
    [Phone, Required]
    public int PhoneNumber { get; set; }

    public Person(int PhoneNumber, string Name, string Email = null, int? Cin = null, string Address = null)
    {
        this.PhoneNumber = PhoneNumber;
        this.Name = Name;
        this.Email = Email;
        this.Address = Address;
        this.Cin = Cin;
    }

    public Person()
    {
    }
}

這是我的Customer類：

public class Customer : Person
{
    public List<Device> CustomerDevices { get; set; }

    public Customer(int PhoneNumber, string Name, string Email = null, int? Cin = null, string Address = null)
        : base(PhoneNumber, Name, Email, Cin, Address)
    {
    }

    public Customer() : base()
    {
    }
}

Answer 1

您的代碼示例中的問題是您應該將set添加到您的Id屬性，以便實體框架可以設置自動生成的 id。

Answer 2

我認為你的id屬性需要有一個 setter

public int Id { get; }              // not work
public int Id { get; set; }         // work
public int Id { get; private set; } // also work

你可以改變類Person

public class Person
{
    [Key]
    public int Id { get; private set; }
    [EmailAddress]
    public string? Email { get; set; }
    public int? Cin { get; set; }
    public string? Address { get; set; }
    [Required]
    public string Name { get; set; }
    [Phone, Required]
    public int PhoneNumber { get; set; }

    public Person(int PhoneNumber, string Name, string Email = null, int? Cin = null, string Address = null)
    {
        this.PhoneNumber = PhoneNumber;
        this.Name = Name;
        this.Email = Email;
        this.Address = Address;
        this.Cin = Cin;

    }
    public Person()
    {

    }
}