Is it possible to use EL conditional operator in action attribute?

问题

The conditional operator works in many attributes like "rendered" "value" and others.

But it does not work in action? Or am I doing it wrong?

<h:commandLink action="#{true ? bean.methodTrue() : bean.methodFalse()}"/>

Error: javax.el.ELException: Not a Valid Method Expression

(I realized it using primefaces ajax action attribute)

回答1:

This is not supported. The action attribute is supposed to be a MethodExpression, but the conditional operator makes it a ValueExpression syntax. I don't think this will ever be supported for MethodExpressions in EL.

You have basically 2 options:

1. Create a single action method which delegates the job.

   <h:commandButton ... action="#{bean.method}" />
   

   with

   public String method() {
       return condition ? methodTrue() : methodFalse();
   }
   

   If necessary, pass it in as method argument by #{bean.method(condition)}.

2. Or, conditionally render 2 buttons.

   <h:commandButton ... action="#{bean.methodTrue}" rendered="#{bean.condition}" />
   <h:commandButton ... action="#{bean.methodFalse}" rendered="#{not bean.conditon}" />
   

来源：https://stackoverflow.com/questions/10473743/is-it-possible-to-use-el-conditional-operator-in-action-attribute