Changing value in drop-down based on selected value in another drop-down

Question

Hi,
I have two drop-downs - changing value in Combo1, should cause the form to be submitted and values to be populated in Combo 2.
Approaches i tried - 1) I am using an ActionListener. I am having a valueChange method which accepts an action event. However this appraoch is not working for me. 2) I was wondering if I could use Javacsript to catch the OnChange event , the javascript function would call an appropirate method in my ActionListener. I know in Struts its straightforward, but how do i achive the same here in JSF.
Any tips would be helpful.
Thanks
PS: I already came across some threads in the forum, but could not get an answer. Also, I have a retsriction in terms of using Action LIsteners itself.

Answer 1

Try using ValueChangeListener instead of ActionListener.
Here's a working example of a ValueChangeListener. You can customize it and use it for your application.
The JSP will look like this:
     <h:selectOneMenu value="#{globalsBean.selectedFirst}"
          valueChangeListener="#{globalsBean.changeList}" onchange="submit()">
          <f:selectItems value="#{globalsBean.first}" />
     </h:selectOneMenu>
     <h:selectOneMenu value="#{globalsBean.selectedSecond}">
          <f:selectItems value="#{globalsBean.second}" />
     </h:selectOneMenu>The globalsBean will look like this:
public class GlobalsBean extends Bean {
     ArrayList first;
     ArrayList second;
     String selectedFirst;
     String selectedSecond;
     public GlobalsBean() {
          first = new ArrayList();
          second = new ArrayList();
          first.add(new SelectItem("1", "1"));
          first.add(new SelectItem("2", "2"));
          selectedFirst = "1";
          selectedSecond = "";
          second.add(new SelectItem("White", "White Cows"));
          second.add(new SelectItem("Brown", "Brown Cows"));
          second.add(new SelectItem("Green", "Green Cows?!?"));
     public ArrayList getFirst() {
          return first;
     public ArrayList getSecond() {
          return second;
     public String getSelectedFirst() {
          return selectedFirst;
     public void setSelectedFirst(String selected) {
           selectedFirst = selected;
     public String getSelectedSecond() {
          return selectedSecond;
     public void setSelectedSecond(String selected) {
           selectedSecond = selected;
     public void changeList(ValueChangeEvent event) throws AbortProcessingException{
          second = new ArrayList();
          String newValue = (String)event.getNewValue();
          setSelectedFirst(newValue);
          if (newValue.equals("1")) {
               second.add(new SelectItem("White", "White Cows"));
               second.add(new SelectItem("Brown", "Brown Cows"));
               second.add(new SelectItem("Green", "Green Cows?!?"));
          } else if (newValue.equals("2")) {
               second.add(new SelectItem("White/Black", "White Cows with Black spots"));
               second.add(new SelectItem("Black", "Black Cows"));
          setSelectedSecond("");
}Let me know how it works out for you.
CowKing