PRB: Unknown Member Error Using Thisformset.ActiveControl

ID: Q156343

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 5.0, 6.0

SYMPTOMS

Referencing an active control with Thisformset.ActiveControl.<property or method> generates the following error message in Visual FoxPro version 5.0:

Unknown member ACTIVECONTROL

Referencing an active control in this manner does not generate an error in Visual FoxPro 3.0 and 3.0b.

RESOLUTION

Reference the active control as follows:


   Thisformset.ActiveForm.ActiveControl.<property or method>

This works properly in all versions of Visual FoxPro.

STATUS

This behavior is by design.

MORE INFORMATION

This is undocumented in Visual FoxPro 3.0 and is not intended to work, as Formset objects do not have an ActiveControl property in any version of Visual FoxPro.

Steps to Reproduce Behavior

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


   * Start of code example
   *
   PUBLIC oFormset
   oFormset = CREATEOBJECT('formset')
   oFormset.ADDOBJECT('form1','frm')
   oFormset.form1.VISIBLE=.T.
   oFormset.SHOW()

   DEFINE CLASS frm AS FORM
      CAPTION = "Click on Form to Demonstrate Error"
      ADD OBJECT text1 AS TEXTBOX WITH ;
         TOP = 100, ;
         LEFT = 120

      PROCEDURE CLICK
         * This will not generate an error in VFP 3.0 or 3.0b
         WAIT WINDOW THISFORMSET.ACTIVECONTROL.NAME TIMEOUT 3
      ENDPROC

   ENDDEFINE
   *
   * End of code example

Click anywhere on the form (outside of the text box).

In Visual FoxPro 5.0 or 6.0, the error "Unknown member ACTIVECONTROL" appears. In Visual FoxPro 3.0 or 3.0b, "TEXT1" is displayed in the WAIT WINDOW.

The preceding code works without error in any version of Visual FoxPro if modified as follows:


      PROCEDURE CLICK
      * This will not generate an error in VFP 3.0, 3.0b, or 5.0
      WAIT WINDOW THISFORMSET.ACTIVEFORM.ACTIVECONTROL.NAME TIMEOUT 3
     ENDPROC

Additional query words:

Keywords : kbVFp kbVFp500 kbVFp600 FxprgClassoop
Version : WINDOWS:5.0,6.0
Platform : WINDOWS
Issue type :