title: JavaFX : Binding button disable property to ComboBox and DatePicker
body: <p>My fxml contains a TextField, a ComboBox, a DatePicker and a Button that should only be enabled when the objects above are not empty.</p>
  
  <pre><code>@FXML private TextField numText;
  @FXML private ComboBox societeComboBox;
  @FXML private DatePicker dateCreationPicker; 
  
  @FXML private Button ajoutBtn; 
  </code></pre>
  
  <p>i figured out how to bind the disable property of the button to the TextField but i can't figure out how to do the same for the ComboBox and the DatePicker.</p>
  
  <pre><code> ajoutBtn.disableProperty().bind(
          Bindings.isEmpty(numText.textProperty())  );
  </code></pre>