May I know how to use a page as a parameter to a data transform? We try several ways but still failed.

e.g. A B are two data transforms defined in case type class. A call B with a page as a parameter. The page is related a data class said CCC-Data-ddd.

/// In called side, B:

we define a parameter said PageData as type "Page name"

and define page PageData to class CCC-Data-ddd in "Pages & Classes" tab

In steps of B, we access property from PageData with "PageData.xxx"

Then B is saved and checked in normally.

/// In case type class

There's a page related to class CCC-Data-ddd defined in case type class, said "ReqData"

/// In calling side, A.

We add a step to call B with one of below several parameter values:

ReqData     (without "")

.ReqData     (without "")

"ReqData"     (with "")

".ReqData"     (with "")

Then A is saved and checked in normally.

However, with each of the para value of above 4 options, in run time, an error is reported like below:

"The Flow Action yyy transform rule A failed: PageData.xxx!=NULL ClipboardPage, can not execute query .xxx with 0 parameters ...  on null page

Seems the page ReqData is not passed from A to B successfully.

Could you kindly advise? Thanks.