Question

I found a tutorial that is very close to what I am looking to do: http://www.andygibson.net/blog/tutorial/binding-dynamic-multi-select-checkboxes-with-jsf/

The only change is that I am building my checkboxes within my backing bean instead of in my .xhtml file, but the ‘value’ attributes are not being set correctly.

snippet from my .xhtml file:

<h:form>
<h:panelGrid binding="#{myBean.myGrid}"></h:panelGrid>
<h:commandButton id="submit" type="submit">
</h:form>

snippet from myBean:

public HtmlPanelGrid getMyGrid()
{
  resultGrid = new HtmlPanelGrid();
  resultGrid.setColumns(2)
  List children = resultGrid.getChildren();

  FacesContext myFacesInstance = FacesContext.getCurrentInstance();
  Application myApp = myFacesInstance.getApplication();
  ExpressionFactory expFactory = myApp.getExpressionFactory();

  SelectItem tempSelectItem;
  String valuStringExpression;
  ValueExpression valExpression;

  //create panel for the checkboxes
  HtmlSelectManyCheckbox checkboxPanel = new HtmlSelectManyCheckbox();
  checkboxPanel.setLayout("pageDirection");

   List<SelectItem> checkChoiceList = new ArrayList<SelectItem>();

   for (int i=0;i<numChoices;i++)
   {
    valStringExpression = "#{myBean.responseValue["+i+"]}";
valExpression = expFactory.createValueExpression(myFacesInstance.getELContext(), valStringExpression, String.class);        
    tempSelectItem = new SelectItem(valExpression,choiceLabels.get(i));
    checkChoiceList.add(tempSelectItem);
   }

  UISelectItems checkboxList = new UISelectItems();
  checkboxList.setValue(checkChoiceList);
  checkboxPanel.getChildren().add(checkboxList);

  children.add(checkboxPanel);

return resultGrid;
}

The problem is that each checkbox’s value attribute is not properly mapping to my “#{myBean.responseValue[“+i+”]}” properly.

If I pull up ‘View Source” from the web page, the checkbox tag’s value shows up as:

value="ValueExpression[#{myBean.responseValue[0]}]"

I have been googling for hours upon hours and I am stumped. Any help or ideas are greatly appreciated!!

Answer 1

The 1st argument of the SelectItem constructor expects the actual select item value, not some value expression. Fix it accordingly:

Object value = valExpression.getValue(elContext);
tempSelectItem = new SelectItem(value, choiceLabels.get(i));