How to update only one field using Entity Framework?

Question

Here\'s the table

Users

UserId
UserName
Password
EmailAddress

and the code..

Answer 1

You can tell EF which properties have to be updated in this way:

public void ChangePassword(int userId, string password)
{
  var user = new User { Id = userId, Password = password };
  using (var context = new ObjectContext(ConnectionString))
  {
    var users = context.CreateObjectSet();
    users.Attach(user);
    context.ObjectStateManager.GetObjectStateEntry(user)
      .SetModifiedProperty("Password");
    context.SaveChanges();
  }
}