Question

我刚开始编码第一个approch刚才开始学习我已经创建了两个类，但是显示了这样的错误。必须在具有一个*关系的类中进行更改。这两个类是，

[Table("Department")]
    public class Department
    {
        [Key]
        public int Did { get; set; }
        public int DName { get; set; }
        public virtual Student student { get; set; }
    }

[Table("Student")]
    public class Student
    {
        [Key]
        public int id { get; set; }
        public string name { get; set; }
        public int age { get; set; }
        public int? department { get; set; }
        [ForeignKey("department")]
        public virtual Department Department { get; set; }
    }

我的上下文类：

 public class StudentContext : DbContext
    {
        public StudentContext()

            :base("StudentContext")
        { }
        public DbSet<Student> students { get; set; }
        public DbSet<Department> departments { get; set; }


    }

Answer 1

嗯，首先，你有2个部门属性。您可能希望外键是DepartmentId。那么你需要1对多的学生集合。

// No need for a table attribute if it matches the class name
public class Department
{
    [Key]  // If you called this Id or DepartmentId you would not need the attribute
    public int Did { get; set; }
    public int DName { get; set; }
    public virtual ICollection<Student> Students { get; set; }
}

public class Student
{
    [Key] 
    public int id { get; set; }
    public string name { get; set; }
    public int age { get; set; }
    // EF will make this relationship automatically. But if you like you can keep FK attribute.
    [ForeignKey("Department")]
    public int? DepartmentId { get; set; }
    public virtual Department Department { get; set; }
}

必须在asp.net MVC代码中为一对多关系crud操作显式配置此关联的主要结尾

1 个答案: