What I am looking for is a way to automatically propagate a change from one
drop down list to
another without having to submit the form.
This can be easily done in a pure Java Script approach using an onClick
function. However, this
approach breaks in JSF.
As a very simple example, if dropdown "A" contains values for years, and drop
down "B" contains
values for car models in a given year, you can use JavaScript to change
dropdown "B" when a user
makes a selection from dropdown "A". You do not set up any options in your JSP
in dropdown "B";
the options are contained in the function and the browser puts the right
options in the DOM when
the function is selected.
The change actually works in the browser for a JSF page; however, when the form
is submitted an
error is generated: "formName:carModel invalid value".
It seems like JSF might be doing a validation against the possible options in
the dropdown list to
insure the the option value is valid when compared to that list; because no
options are found, an
error is generated. If this is the case, there are many JavaScript techniques
that will not be
valid in JSF.
Any suggestions or insights would be greatly appreciated.
Mike
--- [EMAIL PROTECTED] wrote:
> Hi!
>
> No the form is submitted (because a ValueChangeListener needs this)
>
> With the following I display the same page again, but this time with the new
> items in the second
> selectbox:
>
> if (event.getComponent().getId()
> > .equalsIgnoreCase("newpartnerMandanten")) {
> > String viewId = "/newpartner.jsp";
> > FacesContext context =
> > FacesContext.getCurrentInstance();
> > UIViewRoot view =
> > context.getApplication().getViewHandler()
> > .createView(context, viewId);
> > view.setViewId(viewId);
> > context.setViewRoot(view);
> > context.renderResponse();
>
>
> -----Ursprüngliche Nachricht-----
> Von: Mike Duffy [mailto:[EMAIL PROTECTED]
> Gesendet: Mittwoch, 14. Dezember 2005 19:34
> An: MyFaces Discussion
> Betreff: Re: AW: Dynamic Drop Down Lists
>
>
> Thx Andreas.
>
> When you make a change in the first select box, does the change automatically
> propogate to
> second
> selectbox without submitting the form (or does the change just affect the
> component tree)?
>
> Mike
>
> --- [EMAIL PROTECTED] wrote:
>
> > HI Mike!
> >
> > I have done it with a ValueChangeListener, it works fine.
> > I get my Values for the BOX from the Database, because I have to update
> > them very quickly. So
> > I'm not sure, if you will do that yourself.
> >
> > Here is my code, perhaps it helps you:
> >
> >
> > <!--FIRST SELECTBOX-->
> > <h:selectOneMenu id="mandanten" styleClass="show"
> > value="#{searchDto.mandant}"
> > valueChangeListener="#{linker.listnewStandortsForSearch}"
> > onchange="submit()" rendered="#{searchDto.showAlleAnzeigenMandant}" >
> > <f:selectItem itemValue="#{searchDto.nullwert}" itemLabel="#{msg.alle}"
> > />
> > <f:selectItems value="#{queryHelper.mandanten}"/>
> > </h:selectOneMenu>
> >
> > <!--SECOND SELECTBOX: DEPENDS ON FIRST SELECTBOX-->
> > <h:selectOneMenu id="standorte" styleClass="show"
> > value="#{searchDto.standort}"
> > rendered="#{searchDto.showAlleAnzeigenStandort}">
> > <f:selectItem itemValue="#{searchDto.nullwert}" itemLabel="#{msg.alle}"
> > />
> > <f:selectItems value="#{queryHelper.standorte}"/>
> > </h:selectOneMenu>
> >
> > //HERE IS THE VALUECHANGEMETHOD:
> >
> > public void listnewStandortsForSearch(ValueChangeEvent event) {
> >
> > qh = (QueryHelper) FacesUtil.getManagedBean("queryHelper");
> > searchDto = (SearchDto) FacesUtil.getManagedBean("searchDto");
> > Long newvalue = null;
> >
> > // Überprüfung ob Wert der Mandanten Combobox einen anderen
> > Wert als 0
> > // (=Alle Anzeigen) liefert
> > if (((Long) event.getNewValue()).compareTo(new Long(0)) != 0) {
> > newvalue = (Long) event.getNewValue();
> > searchDto.setMandant(newvalue);
> >
> > }
> > else {
> > searchDto.setMandant(new Long(0));
> > }
> >
> > //CALL METHOD WHICH TAKES THE VALUES FOR THE 2nd BOX OUT OF THE
> > DATABASE, DEPENDING ON THE
> > SELECTION OF THE FIRST BOX.
> > try {
> > qh.liststandorts(newvalue);
> > }
> > catch (Exception e) {
> > // TODO Auto-generated catch block
> > e.printStackTrace();
> > }
> >
> >
> > //NOT SO INTERESSTING FOR YOU:
> > if (event.getComponent().getId()
> > .equalsIgnoreCase("newpartnerMandanten")) {
> > String viewId = "/newpartner.jsp";
> > FacesContext context =
> > FacesContext.getCurrentInstance();
> > UIViewRoot view =
> > context.getApplication().getViewHandler()
> > .createView(context, viewId);
> > view.setViewId(viewId);
> > context.setViewRoot(view);
> > context.renderResponse();
> > }
> > else {
> > String viewId = "/search.jsp";
> > FacesContext context =
> > FacesContext.getCurrentInstance();
> > UIViewRoot view =
> > context.getApplication().getViewHandler()
> > .createView(context, viewId);
> > view.setViewId(viewId);
> > context.setViewRoot(view);
> > context.renderResponse();
> > }
> >
> > }
> >
> > -----Ursprüngliche Nachricht-----
> > Von: Mike Duffy [mailto:[EMAIL PROTECTED]
> > Gesendet: Mittwoch, 14. Dezember 2005 09:37
> > An: [email protected]
> > Betreff: Dynamic Drop Down Lists
> >
> >
> > Is there any way to create dynamic drop down lists in JSF without using
> > AJAX?
> >
> > Without JSF there are JavaScript techniques that can be used to dynamically
> > change a drop down
> > list (e.g., based on the selection of drop down list A, the values ion drop
> > down list B are
> > populated by an onclick function),
> >
> > However, with JSF, the changes made in JavaScript do not correspond to the
> > values in the
> > component
> > tree on the server, so an error is thrown. I've tried to update the
> > component through a
> > "valueChangeListener", but this also generates an error.
> >
> > Has anyone found a way to do this in JSF? Can you send a link with an
> > example? I Googled
> with
> > no
> > success.
> >
> > Thx.
> >
> > Mike
> >
> > __________________________________________________
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