title: WPF mvvm with entity framework: create save command
body: <p><em>Assumpion: I'm a newbie in this world and I'm learning by doing.</em></p>
  
  <p>I have a menu on the top, with a set of button. Under this, I open various tabs, where I'm managing different data from my database, with entity framework (6.0).  </p>
  
  <p>In one of these tabs, I show my data, with a custom master/slave (list on the left, editable details on the right). How can I understand when user edit at least one value and enable the save button? And what have I to do to write the save command in my code?</p>
  
  <p><strong>Considering I have a lot of classes in my EF model, is there a way to write only one save function for all these classes?</strong></p>
  
  <p>Thanks to all will answer. :-)</p>