According to https://code.google.com/p/primefaces/issues/detail?id=4720, The ComponentUtils.resolveWidgetVar(String expression, UIComponent component)
function is available in Primefaces since 2013. It can be used in EL by the "#{p:widgetVarFromContext(searchExpression, component)}"
function.
This is useful in case of several components have the same id in different NamingContainer
, but are still present in the same view. In this case,
the #{p:widgetVar(searchExpression)}
function only returns the last one found.
I don't understand however how to reference the UIComponent
that must be passed as the second argument from EL. The above mentioned bug report suggests we can refer to it using #{component}
. Can anyone provide me with an example?
The
#{component}
is an implicit EL variable referring the currentUIComponent
in EL scope (see also implicit EL objects). You can usually only refer it in component's HTML attribute or in template text children.E.g. in case of
<h:inputText>
it will reference an instance ofUIInput
class which has among others anisValid()
method.You can also use
binding
attribute to let JSF during view build time put a reference to a component instance in the Facelet scope. This way the component reference will be available anywhere in the Facelet during view render time.See also:
The
p:widgetVarFromContext
is useful when referring to a PrimeFaces widget inside a composite component. There could be more than one instance of your component on the same page. So writingwidgetVar="expression"
andPF('expression')
is out of the question. There would be multiple widgets with the same name. It is then better to omit thewidgetVar
attribute and use the generated one which is unique because it is based on theclientId
.You can't use
#{p:widgetVar('expression')}
within your<cc:implementation>
because it leads to aCannot find component for expression "expression" referenced from "j_id1"
error instead of the expectedPF('widget_expression')
.But you can use
#{p:widgetVarFromContext('expression', cc)}
which will return something likePF('widget_wrapperform_compositecomponent1_expression')
. Thecc
refers to the root of the composite component instance.