How to get the selected value in SelectOneMenu in backing bean

Question

Hello all,
I need your help. I want to have 2 select menus with the second menu's items list are populated based on the selection in the first menu. I don't know how to get the selected value in the backing bean so that I can based on that select menu to populate the second menu's item list. Basically I need to access to the UI Component of the first select Menu and retrieve its selected value.
Could you help me out?
Thank you very much in advance,
Lngo

Answer 1

Hi Lingo,
There r two ways of getting the values into the list. First one is hardcoding the values and the second one is use the list and get the values into the list by firing a query in the database.
Inorder to display the values in the second menu based on the first onces selection we need to add an attribute to the first selectonemenu known as valueChangeListener and we need to sumit the page.
Here is the sample code
<h:selectOneMenu id="catalogue"
                              binding="#{urbean.catalogue}" onchange="submit()"
                              valueChangeListener="#{urbean.categoryValueChange}"
                              <f:selectItem itemLabel="Select Catalogue" itemValue="" />
                              <f:selectItems value="#{urbean.catalogueList}" />
</h:selectOneMenu>
<h:selectOneMenu id="category"
                              binding="#{urbean.category}">     <f:selectItem itemLabel="Select Category" itemValue="" />
                              <f:selectItems value="#{urbean.categoryList}" />
                              <                         </h:selectOneMenu>
now in method called by valuechangelistener we need to write the similar code
public void categoryValueChange(ValueChangeEvent event) {
String rfnum = (String) event.getNewValue();
List categoryList = new ArrayList();
List tempList = new TablenameDAO().getActiveCatByCatalogueID(rfnum);
          for (int i = 0; i < tempList.size(); i++) {
               Tablename tablename = (Tablename ) tempList.get(i);
               String value = "" + tablename .getrfnum();
String label = tablename .getname();
     if (label == null) {
               label = "";
               SelectItem item = new SelectItem(value, label);
               categoryList.add(item);
          bean.setCategoryList(categoryList);
///getActiveCatByCatalogueID (rfnum) should bring the records which r based on the rfnum
if u follow this process i am damsure that u will get the values in to the secondlist based upon the first list
Thanks & Regards
Manidhar