[英]Unable to update Foreign Key in Entity Framework 6
I am trying to do a simple update to the foreign key but the script never get sent over.我正在尝试对外键进行简单的更新,但脚本永远不会被发送。
Here is the code I am using:这是我正在使用的代码:
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. EF6 更新 Persons 表中列的其余部分,但不会更新 Persons 表中的 Contact_Id。
Person entity:个人实体:
public class Person
{
public int Id { get; set; }
public string Name { get; set; }
public List<Contact> ContactList { get; set; }
}
Contact entity:联系实体:
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?我在这里缺少什么?
Please help!请帮忙!
Since you are working with independent association.由于您正在与独立协会合作。 You can either你可以
Adding and removing the relationship from ContactList
, but you need to retrieve from both Person
.从ContactList
添加和删除关系,但您需要从两个Person
检索。
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.或者您可以使用断开连接的对象,但您需要手动管理关系。
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聚苯乙烯
You might need to reconsider adding foreign key value, to make everything easier, updating foreign key just by mentioning the Id.您可能需要重新考虑添加外键值,以简化一切,只需提及 Id 即可更新外键。
This is what I ended up building till the late hours of the morning, chould/should be refactored some more...这就是我最终构建到凌晨的东西,应该/应该再重构一些......
protected static async Task<int> SaveEntity<t>(t obj) where t : BaseModel
{
try
{
using (DatabaseContext db = GetDbContext())
{
//get the basemodel/fk reference properties
IEnumerable<PropertyInfo> props = obj.GetType().GetProperties().Where(p => p.PropertyType.BaseType == typeof(BaseModel));
if (obj.Id <= 0)
{//insert
db.Entry(obj).State = EntityState.Added;
//set fk reference props to unchanged state
foreach (PropertyInfo prop in props)
{
Object val = prop.GetValue(obj);
if (val != null)
{
db.Entry(val).State = EntityState.Unchanged;
}
}
//do insert
return await db.SaveChangesAsync();
}
else
{//update
//get the posted fk values, and set them to null on the obj (to avaid dbContext conflicts)
Dictionary<string, int?> updateFKValues = new Dictionary<string, int?>();
foreach (PropertyInfo prop in props)
{
BaseModel val = (BaseModel)prop.GetValue(obj);
if (val == null)
{
updateFKValues.Add(prop.Name, null);
}
else
{
updateFKValues.Add(prop.Name, val.Id);
}
prop.SetValue(obj, null);
}
//dbContext creation may need to move to here as per below working example
t dbObj = (t)db.Set(typeof(t)).Find(new object[] { obj.Id }); //this also differs from example
//update the simple values
db.Entry(dbObj).CurrentValues.SetValues(obj);
//update complex values
foreach (PropertyInfo prop in props)
{
Object propValue = null;
if (updateFKValues[prop.Name].HasValue)
{
propValue = (BaseModel)db.Set(prop.PropertyType).Find(new object[] { updateFKValues[prop.Name] });
}
prop.SetValue(dbObj, propValue);
if (propValue != null)
{
db.Entry(propValue).State = EntityState.Unchanged;
}
}
//do update
return await db.SaveChangesAsync();
}
}
}
catch (Exception ex)
{
ExceptionHelper.Log(ex);
throw;
}
}
Basically this happens because EntryState.Modified
just looks for scalar properties ( primitive types) and with independent association (your case) you don't have it.基本上发生这种情况是因为EntryState.Modified
只是寻找标量属性(原始类型)并且具有独立关联(您的情况),您没有它。
There is a several ways to achieve this, @Yuliam has pointed some of them and here you can find more.有几种方法可以实现这一点,@Yuliam 指出了其中的一些,在这里您可以找到更多。
This solution worked for me when needing to update the main object and it's foreign key objects attached.当需要更新主对象及其附加的外键对象时,此解决方案对我有用。
public virtual async Task<Result<TEntity>> Update<TEntity>(TEntity entity) where TEntity : class
{
Result<TEntity> returnResult = new Result<TEntity>();
try
{
//get the fk reference properties
IEnumerable<PropertyInfo> props = entity.GetType().GetProperties().Where(p => p.PropertyType.BaseType == typeof(object));
//set fk reference props to modified state
foreach (PropertyInfo prop in props)
{
Object val = prop.GetValue(entity);
if (val != null)
{
dbContext.Entry(val).State = EntityState.Modified;
}
}
dbContext.Entry(entity).State = EntityState.Modified;
await dbContext.SaveChangesAsync();
returnResult.SetSuccess(result: entity);
}
catch (Exception e)
{
log.Error(e);
returnResult.SetError(exception: e);
}
return returnResult;
}
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