c# - C# 中 Migration 文件夹类内的意外操作

Question

在编写初始模型后，我从控制台使用命令 Add-Migration 添加了迁移。创建了三个迁移文件，但我在文件中进行了一些意外和未定义的操作。

学生类(class):

public class Student

{
    public string StudentsUserId { get; set; }
    public bool is_accepted { get; set; }
    public int Number_preferences { get; set; }

    public List<Preference> Preferences { get; set; }
    public List<Offers> Offers { get; set; }
    public List List { get; set; }
    [NotMapped]
    public IList<Courscategory> courshistory { get; set; }

}

优惠类:

   public class Offers
    {
        public string CourseID { get; set; }

        public string SupervisorUserId { get; set; }
        public string Department { get; set; }
        public string Email { get; set; }
        public int Max_student { get; set; }
        public string CourseName { get; set; }
        public string CourseDescription { get; set; }
        public DateTime Start { get; set; }
        public DateTime End { get; set; }
        public int CourseAvaialbility { get; set; }
        public string Requirements { get; set; }
        public bool IsFull { get; set; }


        public Supervisors Supervisor { get; set; }  //Supervisor is a separate class
        public List<CList> List { get; set; }

    }
}

列出类:

   public class List
    {
        public string CourseID { get; set; }
        public string CourseName { get; set; }
        public string StudentsUserId { get; set; }
        public string SupervisorUserId { get; set; }
        public DateTime StartDate { get; set; }
        public DateTime EndDate { get; set; }

        public Offers Offer { get; set; }
        public List<Students> Studnets { get; set; }
        public List<Supervisors> Supervisor { get; set; }

        public List<Preference> Preference { get; set; }

    }
}

迁移文件中的代码:

migrationBuilder.CreateTable(
            name: "CStudents",
            columns: table => new
            {
                StudentsUserId= table.Column<string>(nullable: false),
                is_accepted = table.Column<bool>(nullable: false),
                Number_preferences = table.Column<int>(nullable: false),
                ListCourseID = table.Column<string>(nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_CStudents", x => x.StudentsUserId);
                table.ForeignKey(
                    name: "FK_StudentsUserId_List_ListCourseID",
                    column: x => x.ListCourseID,
                    principalTable: "List",
                    principalColumn: "CourseID",
                    onDelete: ReferentialAction.Restrict);
            });

初始模型代码:

public class CFE_CrazyLabContext : DbContext
{
    public CFE_CrazyLabContext(DbContextOptions<CFE_CrazyLabContext> options)
        : base(options)
    {
    }

    public DbSet<LearnAngebot.Models.CStudents> Students{ get; set; }      

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {

        modelBuilder.Entity<CStudents>().HasKey(o => o.StudentsUserId);

    }
}

ListCourseId 在 Student 类中不存在，不是该类的变量。不知道这些操作是如何添加的。

Answer 1

编辑后，看起来你有点混淆了关系，根据你的评论，你说 Entity Framework 为你创建的外键是错误的，这是因为你交换了它。您添加到 StudentsUserId 中的 List 类的 FKey 目前只是一个额外的字段，没有什么特别之处。

在 student 类中，列表类的链接应该如下所示

public class Student

{
    public string StudentsUserId { get; set; }
    public bool is_accepted { get; set; }
    public int Number_preferences { get; set; }

    public List<Preference> Preferences { get; set; }
    public List<Offers> Offers { get; set; }

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

    [NotMapped]
    public IList<Courscategory> courshistory { get; set; }

}

在您的 List 类中，它应该如下所示:

public class List
    {
        public string CourseID { get; set; }
        public string CourseName { get; set; }
        public string StudentsUserId { get; set; }
        public string SupervisorUserId { get; set; }
        public DateTime StartDate { get; set; }
        public DateTime EndDate { get; set; }

        public Offers Offer { get; set; }
        public Student Student { get; set; }

        public List<Supervisors> Supervisor { get; set; }
        public List<Preference> Preference { get; set; }
    }

生成的额外字段“ListCourseId”感觉就像是 EF 按照 [Table]+[PKey] 模式自动生成的字段。