Entity Framework Attach not updating DB - database

Question

I have the following problem: when i try to change the town of a user by passing the modified user entry to my ModifyUser method in my UserService class everything seems ok but the changes are not applied in the database.
I tried the solutions from similar problems i found on stackoverflow but none of them seem to work.
As they say "a picture is worth a thousand words" take a look at this, since its easier to understand compared to my short explanation.
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else if (property == "BornTown")
{
if (this.townService.TownExists(value))
{
User user = this.userService.GetUserByName(username);
Town town = this.townService.GetTownByName(value);
user.BornTown = town;
this.userService.ModifyUser(user);
}
else
{
Console.WriteLine($"Value {value} is not valid.");
throw new ArgumentException($"Town {value} not found!");
}
}
When i pass the user to the ModifyUser the database does not update, and BornTown stays NULL.
public void ModifyUser(User user)
{
using (PhotoShareContext context = new PhotoShareContext())
{
context.Users.Attach(user);
context.Entry(user).State = EntityState.Modified;
context.SaveChanges();
}
}

Answer 1

Or else try below code:
User user = context.users.where(x=>x.username == username).FirstOrDefault();
user.BornTown = town; //string
context.savechanges();

Answer 2

Can you try
context.Users.where(x=>x.username == username).FirstOrDefault();
and don't use any()
Can you check if you are getting the proper username, by again checking the username once you are getting back the value in the function.

Answer 3

Instead of manipulating the navigation properties directly try to manage the entity relation using it's foreign keys:
Town town = this.townService.GetTownByName(value);
user.BornTownId = town.Id;
Keep in mind that if you have not created explicit foreign keys in your model entity you should map the existing one: take a look at "Users" table - see how the foreign key column is named- it should look something like UserTown_Id. Then put it in your model class (you may add foreign key attribute or map it in model builder).
Be careful when adding the new property to your model (it can make your optional relation with "Towns" required).