无法更新实体框架 6 中的外键

Unable to update Foreign Key in Entity Framework 6(无法更新实体框架 6 中的外键)

问题描述

我正在尝试对外键进行简单更新，但脚本从未发送过来.

这是我正在使用的代码:

使用 (var db = new MyContext()){db.Entry<Contact>(newContact).State = EntityState.Modified;newContact.ContactOwner = db.Person.Find(3);db.SaveChanges();}

EF6 更新 Persons 表中的其余列，但不更新 Persons 表中的 Contact_Id.

个人实体:

公共类Person{公共 int ID { 获取；放;}公共字符串名称 { 获取；放;}公开名单<联系方式>联系人列表 { 获取；放;}}

联系实体:

公开课联系方式{公共 int ID { 获取；放;}公共字符串电子邮件{获取；放;}公共字符串 TelNo { 获取；放;}公共人员联系人所有者 { 获取；放;}}

我在这里错过了什么?

请帮忙！

因为您正在与独立协会合作.你可以

• 在 ContactList 中添加和删除关系，但您需要从两个 Person 中检索.

  db.Entry(newContact).State = EntityState.Modified;var p1 = db.Set().Include(p => p.ContactList).FirstOrDefault(p =>p.Id == 1);p1.ContactList.Remove(newContact);var p3 = db.Set().Include(p => p.ContactList).FirstOrDefault(p => p.Id == 3);p3.ContactList.Add(newContact);db.SaveChanges();

• 或者你可以使用断开的对象，但是你需要手动管理关系.

  db.Entry(newContact).State = EntityState.Modified;var p1 = 新人 { Id = 1 };db.Entry(p1).State = EntityState.Unchanged;var p3 = 新人 { Id = 3 };db.Entry(p3).State = EntityState.Unchanged;var manager = ((IObjectContextAdapter)db).ObjectContext.ObjectStateManager;manager.ChangeRelationshipState(newContact, p1, item => item.ContactOwner,实体状态.已删除)；manager.ChangeRelationshipState(newContact, p3, item => item.ContactOwner,实体状态.添加)；db.SaveChanges();

附言

您可能需要重新考虑添加外键值，以使一切变得更容易，只需提及 Id 即可更新外键.

有关详细信息，请参阅这篇文章.p>

I am trying to do a simple update to the foreign key but the script never get sent over.

Here is the code I am using:

using (var db = new MyContext())
{
      db.Entry<Contact>(newContact).State = EntityState.Modified;
      newContact.ContactOwner = db.Person.Find(3);
      db.SaveChanges();
}

EF6 update the rest of the column in the Persons table but it is not updating the Contact_Id in Persons table.

Person entity:

public class Person
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List<Contact> ContactList { get; set; }
}

Contact entity:

public class Contact
{
    public int Id { get; set; }
    public string Email { get; set; }
    public string TelNo { get; set; }
    public Person ContactOwner { get; set; }
}

What am I missing here?

Please help!

Since you are working with independent association. You can either

• Adding and removing the relationship from ContactList, but you need to retrieve from both Person.

  db.Entry(newContact).State = EntityState.Modified;
  
  var p1 = db.Set<Person>().Include(p => p.ContactList)
      .FirstOrDefault(p =>p.Id == 1);
  p1.ContactList.Remove(newContact);
  
  var p3 = db.Set<Person>().Include(p => p.ContactList)
      .FirstOrDefault(p => p.Id == 3);
  p3.ContactList.Add(newContact);
  
  db.SaveChanges();
  

• Or you can use disconnected object, but you need to manually manage the relationship.

  db.Entry(newContact).State = EntityState.Modified;
  
  var p1 = new Person { Id = 1 };
  db.Entry(p1).State = EntityState.Unchanged;
  var p3 = new Person { Id = 3 };
  db.Entry(p3).State = EntityState.Unchanged;
  
  var manager = ((IObjectContextAdapter)db).ObjectContext.ObjectStateManager;
  manager.ChangeRelationshipState(newContact, p1, item => item.ContactOwner,
       EntityState.Deleted);
  manager.ChangeRelationshipState(newContact, p3, item => item.ContactOwner,
       EntityState.Added);
  
  db.SaveChanges();
  

PS

You might need to reconsider adding foreign key value, to make everything easier, updating foreign key just by mentioning the Id.

See this post for more information.

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