JavaServer Faces - How to get the selected value in SelectOneMenu in backing bean

You can just retrieve it by the valuebinding of the component. You don't need componentbinding.

<h:selectOneMenu value="#{myBean.selectedItem}">
<f:selectItems value="#{myBean.selectItems}" />
</h:selectOneMenu>
...
<h:commandButton value="submit" action="#{myBean.submit}" />
private T selectedItem; // + getter + setter
public void submit() {
System.out.println(selectedItem); // the selectedItem is just available in here.
}
BalusCa at 2007-7-10 14:21:21 > 

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

mandihara at 2007-7-10 14:21:21 >

Thank you both for the help. I am able to populate the second select menu items dynamically based on the first menu selected value and rerender it with ajax4jsf help. Now I have the problem with the select menu is being inside a dataTable. So if a user select 1 value in the first menu on the 1st row, the second menu would be populated with list of choices, and this new list of choices would also shown on the 2nd row when the whole table is rerendered by ajax4jsf, while the user has not make any selection on the second row's first menu. How could I seperate the 2 rows? I am currenyly binding the second selectItems to the same property in backing bean and that's why once its updated on first row, the second row will have the same value. How can I have 2 seperate selectItems binding to seperate rows in dataTable? I find this hard because row in dataTable is generated not controlled by my code.

Thanks a lot,

Lngo

lngo77a at 2007-7-10 14:21:21 >

Hi BalusC,

Could you elaborate more about the row object? I think that might be what I need. I need the second menu items be populated based on the selected value of the first menu on THE SAME ROW. But I have now is the second menu's select items binding have the scope of whole dataTable.

Please show me more specific how to put the select items in a row scope.

This is what I have

<h:dataTable id="tbl" value="#{advisingForm.formData.courses}" var="cc" >
<h:column>
<f:facet name="header">
<h:outputText value="Course" style="text-decoration: underline; font-weight: bold"/>
</f:facet>
<h:selectOneMenu id="dept" value="#{cc.dept}" valueChangeListener="#{advisingForm.courseChangeListener}">
<f:selectItems value="#{advisingForm.subjectList}"/>
<a4j:support event="onchange" action="#{advisingForm.dummy}" reRender="tbl"/>
</h:selectOneMenu>
</h:column>
<h:column>
<f:facet name="header">
<h:outputText value="Number" style="text-decoration: underline; font-weight: bold"/>
</f:facet>
<h:selectOneMenu id="number" value="#{cc.number}" valueChangeListener="#{advisingForm.numberChangeListener}">
<f:selectItems value="#{advisingForm.numberList}"/>
</h:selectOneMenu>
</h:column>
</h:dataTable>
The problem is the advisingForm.numberList is shared for all rows, when it's changed on 1 row, all other row see the change even those row's first select menu is not selected yet.
Tons of thanks,
LNgo
lngo77a at 2007-7-10 14:21:21 >