A reference tag <pega:reference name='D_TestCPL[Param1:"TEST"].pxResultCount' /> gives the error
Section 'TestDP' execution error on page 'pyTempPage' of class 'Work-'. : The reference D_TestCPL[Param1:"TEST"].pxResultCount is not valid. Reason: declare page parameters not supported by PropertyReference
Similarly a reference to <pega:withPage name='D_TestCPL[Param1:"TEST"]'> gives the error
Section 'TestDP' execution error on page 'pyTempPage' of class 'Work-'. : invalid page name: D_TestCPL[Param1:"TEST"]. Details: Invalid value for aName passed to com.pega.pegarules.data.internal.clipboard.ClipboardPageImpl.setName(String).
How can one access parameter-ized data pages from Pega JSP tags?
I believe that this is not a supported feature of Parameterized Data Pages. I would have to double check with @SALIK, but I'm fairly positive that you cannot directly reference a Parameterized Data Page in a section.
It looks like you want to iterate over a data page that is parameterized potentially... I believe the way that I have historically done this is to create a second un-parameterized data page and load it based on a known clipboard page value (ie: D_TestCPLRouting, read only, loaded from Data Transform, Primary = D_TestCPL[Param1:pyWorkPage.param1Val])
Then iterate over D_TestCPLRouting.
Does this make sense?
Update: I checked the PDN Content on parameterized data pages and can confirm that you cannot refer to a data page with the inline parameter syntax in any UI rules.
It looks like all the parameter syntax is doing is populating a parameter page so I tried putting the parameters directly on the current parameter page using <% java %> immediately before the the JSP tag's reference to the Data Page and then referring to the Data Page without parameters. This approach seems to work but I haven't tested it extensively.
Recently I ran into a similar issue but with a R-O-Corr rule and filed BUG-363638 after discussing with Ken & Kalim. However, this bug was then marked as 'Resolved-Rejected' and this MESH post was referenced.
I just implemented a workaround and thought I'd share. I created an RDE that gets the desired value from a Parameterized Data Page. The corresponding Property is then used in my Corr Rule.