PRB: @...GET...NAME Object References Change with Read Level (156178)

MORE INFORMATION

The NAME keyword creates an object reference for controls created with the DEFINE WINDOW, @ ... GET, and @ ... EDIT commands, allowing you to manipulate these objects' properties, events, and methods.

Steps to Reproduce Behavior

1. Run the following code from a program (.prg) file:

      * Start of code example
      *
      DEFINE WINDOW Wind1 AT 0, 0 SIZE 15, 50 TITLE "1st Screen" ;
         SYSTEM FLOAT NAME oForm1
      ACTIVATE WINDOW Wind1
      @ 1, 10 SAY "Press Enter to go to 2nd screen"
      @ 3, 11 SAY "1st screen get " GET lcGet1 SIZE 1, 17 ;
         DEFAULT " " WHEN when1() VALID valid1() NAME loGet1
      READ
   
      RELEASE WINDOW Wind1
   
      FUNCTION when1
         oForm1.Pageframe1.Page1.loGet1.Value = "123"
      ENDFUNC
   
      FUNCTION valid1
         DO Screen2
      ENDFUNC
   
      FUNCTION Screen2
   
         DEFINE WINDOW Wind2 AT 0, 0 SIZE 10,55 TITLE "2nd Screen ";
            SYSTEM FLOAT NAME oForm2
         ACTIVATE WINDOW Wind2
         @ 3, 6  SAY "2nd screen get " GET lcGet2 SIZE 1, 17 ;
            DEFAULT " " WHEN When2() NAME loGet2
         READ
   
         RELEASE WINDOW Wind2
         CLEAR READ ALL
      ENDFUNC
   
      FUNCTION When2
         oForm2.Pageframe1.Page1.lo_Get2.Value = "123"
      ENDFUNC
      *
      * End of code example
   						

2. Note that code in the When1 function successfully references the Value property of the @...GET command in the first screen. Press enter from 1st Screen to go to the second Screen.
3. The error "Unknown member LO_GET2" occurs as 2nd Screen appears. The following code refers to a nonexistant member since the object loGet2 is actually contained in oForm2.Pageframe1.Page2:

         oForm2.Pageframe1.Page1.loGet2.Value = "123"
   						

A generic workaround for this behavior is to use the following code to determine the current READ level and insert the current READ level into the object reference with Macro Substitution. For example, change the code for the function When2 in the code sample above to read as follows:

   * Start of code example
   *
   FUNCTION When2
      LOCAL lcPageNumber
      lcPageNumber=ALLTR(STR(RDLEVEL()))
      oForm2.Pageframe1.Page&lcPageNumber..loGet2.Value = "456"
   ENDFUNC
   *
   * End of code example
				

This stores the current READ level to lcPageNumber and substitutes it back into the object reference. This allows the object loGet2 to be referenced regardless of READ level.