title: how to add items to Qcombobox with its unique Id
body: <p>Do you have any idea to add items into Qcombobox?</p>
  
  <p>as the time the user selects the item,we can retrieve the unique Id's of selected item?</p>
  
  <p>suppose that we have:</p>
  
  <pre><code>=============
  | ID | NAME |
  =============
  | 1  |   A  |
  =============
  | 2  |   B  |
  =============
  | 3  |   C  |
  =============
  | 4  |   D  |
  =============
  </code></pre>
  
  <p>AND we want to show only NAME's column in QCombobox, but when one of the items had selected,we can access to ID of selected item.</p>