When subclassing an activex control, for example Microsoft ListView control in a prg file, the only syntax that worked to dynamically instantiate the appropriate control depending on the Windows version wether NT4 or W2K was the following:

DEFINE CLASS myclass AS OLEControl
OLEClass = EVALUATE("IIF('5'$ OS(),'MSComctlLib.ListViewCtrl.2','COMCTL.ListViewCtrl.1')")
NAME='MyClass'
.......
ENDDEFINE

If I move the evaluation to a procedure which returns the character string of the control name, for example:

DEFINE CLASS myclass AS OLEControl
OLEClass = GetName() && or EVALUATE("GetName()")
NAME='MyClass'
.......
ENDDEFINE

PROCEDURE GetName
DO CASE
CASE '5' $ OS()
RETURN 'MSComctlLib.ListViewCtrl.2'
CASE '4' $ OS()
RETURN 'COMCTL.ListViewCtrl.1'
ENDCASE
ENDPROC

the error "Invalid subscript reference" occurs when trying to instantiate an object of 'MyClass'.

I'd appreciate any explanation of this behavior.

Regards,