Dependant choice lists

Question

Hi,
I would like to be able to present the user with two dropdown lists, with the data from the second one dependant on the first. I understand with 10g this is somewhat simpler due to the introduction of primaryClientAction. I thought of using the query type facility within JHeadstart to read a value from the session Data to populate the second list. My question ? Is this possible without having to submit the form (assuming that the value is only going to get set on the sessionData once the form has been submitted). Is there a way that I could store the value on the sessiondata using a javascript function on my first choice list ??
Thanks,
Brent Harlow

Answer 1

Hi Peter,
Thanks for the reply ! Seemed somewhat daunting at first but not bad once I tried it out. Not 100% successful yet though. I thought that I would first try it out populating a table on a separate page to make sure I had the basics right. First problem is that "'<%=sessionData.getAttribute("controller")%>" does not seem to be getting resolved - the alert(xmlHTTP.responseText) returns "404 Error : Resource /Choicedemo/<%9cessionData.getAttribute("controller")xtarget......"do I need to include something else in my javascript or struts-config ? Secondly, when I replace the code above and hard-code in the web url, the action returns success but the forward table page is not displayed ?? Here is my code
struts-config
      <action path="ModuleRouter" type="oracle.jheadstart.controller.struts.action.DynamicActionRouter">
         <set-property property="forwardParameterName" value="targetGroup"/>
         <set-property property="attributeNameParameter" value="targetCondition"/>
         <set-property property="attributeValueParameter" value="targetConditionValue"/>
         <set-property property="defaultForward" value="Studies"/>
         <set-property property="defaultPreviousForward" value="false"/>
         <forward name="Studies" path="StudiesRouter"/>
         <forward name="Kits" path="KitsRouter"/>
      </action>
      <action path="StudiesRouter" type="oracle.jheadstart.controller.struts.action.ActionRouter">
         <set-property property="defaultForward" value="initial"/>
         <forward name="initial" path="GetStudiesSet"/>
         <forward name="browse" path="BrowseStudiesSet"/>
         <forward name="insert" path="GetDefaultStudies"/>
         <forward name="save" path="SaveStudies"/>
         <forward name="delete" path="DeleteStudies"/>
         <forward name="firstPoplistChanged" path="getSecondPoplist"/>
         <forward name="groupPage" path="/WEB-INF/page/StudiesPage.uix"/>
      </action>
      <action path="getSecondPoplist" type="oracle.jheadstart.controller.struts.action.GetDataObjectSet">
         <set-property property="dataObjectInterface" value="hmdclinical.choicedemo.model.invkitdetail"/>
         <set-property property="dataObjectSetName" value="KitsSet"/>
         <set-property property="isUpdatable" value="true"/>
         <set-property property="rangeSize" value="30"/>
         <set-property property="queryType" value="SecondPoplistQuery"/>
         <set-property property="attributeNames" value="firstPoplistValue"/>
         <set-property property="useAttributeNameAsKey" value="false"/>
         <forward name="success" path="/WEB-INF/page/KitsTablePage.uix"/>
         <forward name="userError" path="/WEB-INF/page/KitsTablePage.uix"/>
         <forward name="dataObjectNotFound" path="/WEB-INF/page/KitsTablePage.uix"/>
      </action>my javascript that is being called from the onChange handler
function firstPoplistChanged(item)
  if (item.selectedIndex >0)
    // This is a url that will invoke a specific forward on
    // a specific actionRouter in your Struts config file.
    // var url = '<%=sessionData.getAttribute("controller")%>?targetGroup=Studies&targetCondition=firstPoplistChanged&targetConditionValue=true';
    var url = 'http://192.168.0.39:8989/Choicedemo/StartChoicedemo.do?targetGroup=Studies&targetCondition=firstPoplistChanged&targetConditionValue=true';
    // Add a parameter to the URL that holds the selected
    // value in the first poplist
    url += '&firstPoplistValue='+item.options[item.selectedIndex].value;
    alert(url)
    // Invoke this URL
    var xmlHTTP = new ActiveXObject("Microsoft.XMLHTTP");
    xmlHTTP.open("GET",url, false);
    xmlHTTP.send();
    // Decomment this alert to see what you actually got back
    // from the server.
    alert(xmlHTTP.responseText);
    // Find the second poplist (you'll need to set its id),
    // and overwrite its content
    // document.getElementById("secondPoplist").outerHTML = xmlHTTP.responseText;
  else
    // If the first poplist is not selected, clear the
    // second one.
    // document.getElementById("secondPoplist").innerHTML = "";
    alert("Item selected index <= 0")
}and finally the oc4j debug showing me that the getSecondPoplist action was successful
22:42:17 DEBUG (DynamicActionRouter) -Forward returned: Studies
22:42:17 DEBUG (JhsRequestProcessor) -Execute StudiesRouter
22:42:17 DEBUG (ActionRouter) -Forward returned: firstPoplistChanged
22:42:17 DEBUG (JhsRequestProcessor) -Execute getSecondPoplist
22:42:17 DEBUG (GetDataObjectSet) -Forward returned: successHow come /WEB-INF/page/KitsTablePage.uix is not being shown then ?
Also..I appreciate you are giving me lots of info here but the last paragraph in your email "Finally, you need to write the simple secondPoplist.jsp that renders the second poplist with the new contents" has got me stumped - Sorry, I dont know where to begin ! How are the normal poplists rendered ? I was trying to find an example.......Im guessing that the JSP just provides the html that creates the poplist - dont understand how to hook it up to the dataObjectSetName. Also, the second list is going to be rather large so I wanted to use a LOV instead of a poplist ? Any pointers ? Do I just need to call the same lovFrame.jsp and pass in the new dataObjectName from the getSecondPoplist action ??
Thanks a million Peter,
Cheers
Brent