title: Update "Simple" Listbox ZK
body: <p>I want to update the listbox when submit button is clicked. the listbox initially consists of a list of JSONObject, after submit button clicked, the list elements changed and the listbox should update with the change but I can't do this. can you help me upadate the listbox?</p>
  
  <p>this is how I put the list of JSONObject in the listbox</p>
  
  <pre><code>&lt;listbox id="userListbox"&gt;
  &lt;listhead&gt;
      &lt;listheader label="Id"&gt;&lt;/listheader&gt;
      &lt;listheader label="Name"&gt;&lt;/listheader&gt;
      &lt;listheader label="Address"&gt;&lt;/listheader&gt;
      &lt;listheader label="Phone"&gt;&lt;/listheader&gt;
  &lt;/listhead&gt;
  &lt;listitem forEach="${userController.list}"&gt;
      &lt;listcell label="${each.id}" &gt;&lt;/listcell&gt;
      &lt;listcell label="${each.name}" &gt;&lt;/listcell&gt;
      &lt;listcell label="${each.address}" &gt;&lt;/listcell&gt;
      &lt;listcell label="${each.phone}" &gt;&lt;/listcell&gt;
  &lt;/listitem&gt;
  </code></pre>
  
  <p></p>
  
  <p>in class UserController:</p>
  
  <pre><code>private List&lt;JSONObject&gt; list;
  
  @Listen("onClick = #submitButton")
  public void onSubmit(Event event) {
      loadUser();
  }
  
  private void loadUser() {
      JSONObject input = new JSONObject();
      input.put("name", nameBox.getText());
  
      list = getUserList(input);
  }
  
  public List&lt;JSONObject&gt; getList() {
      return list;
  }
  
  public void setList(List&lt;JSONObject&gt; list) {
      this.list = list;
  }
  </code></pre>
  
  <p>and I don't know how to update the listbox? thank you for your help.</p>