jsf - <f:selectItems is not returning value in <p:selectOneMenu> -

i have problem getting value of f:selectitems returning label.
here code;

<p:selectonemenu>.     <p:outputlabel value="major diseases"></p:outputlabel>     <p:selectonemenu value="#{datamigeration.mdid}">      <f:selectitem itemlabel="select one" itemvalue="" />     <f:selectitems var="t"                     value="#{datamigeration.majordiseas}"                    itemlabel="#{t.value.mdname}"                    itemvalue="#{t.value}"/>                                  <p:ajax listener="#{datamigeration.getsubdiseasesbymojardisease(datamigeration.mdid)}"              event="change"  update="datamigration"/> </p:selectonemenu>               

here datamigeration class

@managedbean(name="datamigeration") @sessionscoped public class datamigeration{ string mdid; private list<selectitem> majordiseas = new arraylist<selectitem>(); public list<selectitem> getmajordiseas() {     majordiseas = new arraylist<selectitem>();       system.out.println("datamigeration.getmajordiseas():");     list<diseasecategory> majordiseaseslist = new arraylist<diseasecategory>();           majordiseaseslist=datamanager.findallrecords();      (diseasecategory obj : majordiseaseslist) {         majordiseas.add(new selectitem(obj.getmdid(), obj.getmdname()));     }      return majordiseas; }  public void getsubdiseasesbymojardisease(string mdid) {     system.out.println("\n\n\n\n |  value:"+mdid);  } 

but getting mdid=itemlabel of f:selecteditem want itemvalue of f:selectem. somewhere have done before forgot how itemvalue.

your 'f:selectitems' statement wrong. can use 'var' attribute loop through list of complex java objects dynamically create list of selectitem objects. (see http://www.mkyong.com/jsf2/jsf-2-dropdown-box-example/ examples)

but in case, you've created list of selectitem objects in backing bean, reference instead:

<f:selectitems value="#{datamigeration.majordiseas}" />