Entity framework, problems updating related objects
Solution 1:
CurrentValues.SetValues
only updates scalar properties but no related entities, so you must do the same for each related entity:
public Foo Edit(Foo newFoo)
{
var dbFoo = context.Foo
.Include(x => x.SubFoo)
.Include(x => x.AnotherSubFoo)
.Single(c => c.Id == newFoo.Id);
context.Entry(dbFoo).CurrentValues.SetValues(newFoo);
context.Entry(dbFoo.SubFoo).CurrentValues.SetValues(newFoo.SubFoo);
context.Entry(dbFoo.AnotherSubFoo).CurrentValues.SetValues(newFoo.AnotherSubFoo);
context.SaveChanges();
return newFoo;
}
If the relationship could have been removed altogether or have been created you also need to handle those cases explicitly:
public Foo Edit(Foo newFoo)
{
var dbFoo = context.Foo
.Include(x => x.SubFoo)
.Include(x => x.AnotherSubFoo)
.Single(c => c.Id == newFoo.Id);
context.Entry(dbFoo).CurrentValues.SetValues(newFoo);
if (dbFoo.SubFoo != null)
{
if (newFoo.SubFoo != null)
{
if (dbFoo.SubFoo.Id == newFoo.SubFoo.Id)
// no relationship change, only scalar prop.
context.Entry(dbFoo.SubFoo).CurrentValues.SetValues(newFoo.SubFoo);
else
{
// Relationship change
// Attach assumes that newFoo.SubFoo is an existing entity
context.SubFoos.Attach(newFoo.SubFoo);
dbFoo.SubFoo = newFoo.SubFoo;
}
}
else // relationship has been removed
dbFoo.SubFoo = null;
}
else
{
if (newFoo.SubFoo != null) // relationship has been added
{
// Attach assumes that newFoo.SubFoo is an existing entity
context.SubFoos.Attach(newFoo.SubFoo);
dbFoo.SubFoo = newFoo.SubFoo;
}
// else -> old and new SubFoo is null -> nothing to do
}
// the same logic for AnotherSubFoo ...
context.SaveChanges();
return newFoo;
}
You eventually also need to set the state of the attached entities to Modified
if the relationship has been changed and the scalar properties as well.
Edit
If - according to your comment - Foo.SubFoo
is actually a collection and not only a reference you will need something like this to update the related entities:
public Foo Edit(Foo newFoo)
{
var dbFoo = context.Foo
.Include(x => x.SubFoo)
.Include(x => x.AnotherSubFoo)
.Single(c => c.Id == newFoo.Id);
// Update foo (works only for scalar properties)
context.Entry(dbFoo).CurrentValues.SetValues(newFoo);
// Delete subFoos from database that are not in the newFoo.SubFoo collection
foreach (var dbSubFoo in dbFoo.SubFoo.ToList())
if (!newFoo.SubFoo.Any(s => s.Id == dbSubFoo.Id))
context.SubFoos.Remove(dbSubFoo);
foreach (var newSubFoo in newFoo.SubFoo)
{
var dbSubFoo = dbFoo.SubFoo.SingleOrDefault(s => s.Id == newSubFoo.Id);
if (dbSubFoo != null)
// Update subFoos that are in the newFoo.SubFoo collection
context.Entry(dbSubFoo).CurrentValues.SetValues(newSubFoo);
else
// Insert subFoos into the database that are not
// in the dbFoo.subFoo collection
dbFoo.SubFoo.Add(newSubFoo);
}
// and the same for AnotherSubFoo...
db.SaveChanges();
return newFoo;
}
Solution 2:
Just thought I would post the link below as it really helped me understand how to update related entities.
Updating related data with the entity framework in an asp net mvc application
NOTE: I did change the logic slightly that is shown in the UpdateInstructorCourses function to suit my needs.