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Microsoft KB Archive/169111

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Knowledge Base


Article ID: 169111

Article Last Modified on 12/11/1999



APPLIES TO

  • Microsoft Visual FoxPro 5.0 Standard Edition
  • Microsoft Visual FoxPro 5.0a



This article was previously published under Q169111

SYMPTOMS

An error occurs when performing a DODEFAULT function on a Visual FoxPro base class KeyPress method.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

An error occurs when performing a DODEFAULT function to a Visual FoxPro base class method. The DODEFAULT function appears to be referencing an object other than the one in which it is running.

In the code below, the DODEFAULT code is located in the KEYPRESS method of a Form. Pressing the TAB key when the cursor is in the first TextBox of the sample below causes the VALID method of the TextBox to execute but the VALID method of Form appears to be running in addition to the TextBox VALID and a "Property VALUE is not found" error occurs. The Form object does not have a VALUE property. Suspending the program after the error occurs and checking the value of "THIS" verifies that the object reference is the Form rather than the TextBox.

Steps to Reproduce Behavior

  1. Run the sample code below and press the TAB key to move to the next object.

          ****Start of Code
    
          frmTestForm = CREATEOBJECT("MyForm")
          frmTestForm.SHOW
          READ EVENTS
    
          **************************************************
          *-- ParentClass:  basform
          *-- BaseClass:    form
          DEFINE CLASS MyForm AS BASFORM
            PROCEDURE KEYPRESS
            LPARAMETERS NKEYCODE, NSHIFTALTCTRL
    
            && Do not comment the PROCEDURE, ENDPROC or LPARAMETERS lines
            && Comment the following two lines only
    
            WAIT WINDOW "Form Key Press - Child Class"
            DODEFAULT(NKEYCODE, NSHIFTALTCTRL)
    
            ENDPROC
          ENDDEFINE
          *
          *-- EndDefine: MyForm
          **************************************************
          *-- ParentClass:  form
          *-- BaseClass:    form
          DEFINE CLASS BasForm AS FORM
            TOP = 10
            LEFT = 23
            DOCREATE = .T.
            CAPTION = "Test Form"
            KEYPREVIEW = .T.
            NAME = "frmForm1"
    
            ADD OBJECT txtTEXT1 AS TEXTBOX WITH ;
              HEIGHT = 23, ;
              LEFT = 84, ;
              TOP = 24, ;
              WIDTH = 100, ;
              NAME = "txtText1"
    
            ADD OBJECT txtTEXT2 AS TEXTBOX WITH ;
              HEIGHT = 23, ;
              LEFT = 84, ;
              TOP = 84, ;
              WIDTH = 100, ;
              NAME = "txtText2"
    
            ADD OBJECT cmdCOMMAND1 AS COMMANDBUTTON WITH ;
              TOP = 216, ;
              LEFT = 276, ;
              HEIGHT = 27, ;
              WIDTH = 84, ;
              CAPTION = "Close", ;
              NAME = "cmdCommand1"
    
            ADD OBJECT lblLabel1 as LABEL with;
               TOP = 20, ;
            LEFT = 200,;
               CAPTION = "Press the TAB key"
    
              *!* PROCEDURE KEYPRESS
              *!* LPARAMETERS NKEYCODE, NSHIFTALTCTRL
    
              *!* WAIT WINDOW "Form Key Press - Parent Class"
              *!* DODEFAULT(nkeycode, nshiftaltctrl)
              *!* ENDPROC
    
              * Uncomment the above code and comment the contents of
              * the Keypress procedure (Comment the 2 lines of code that
              * are identified to be commented out within the Keypress
              * procedure, which are the lines that start with "WAIT WINDOW"
              * and "DODEFAULT". Do not comment out the PROCEDURE line nor the
              * LPARAMETERS line nor the ENDPROC line) in the BasForm
              * Class definition and the error will not occur.
    
              PROCEDURE txtTEXT1.VALID
                IF EMPTY(THIS.VALUE)
                  WAIT WINDOW "Text1 Valid"
                ENDIF
              ENDPROC
    
              PROCEDURE cmdCOMMAND1.CLICK
                THISFORM.RELEASE()
                CLEAR EVENTS
              ENDPROC
    
          ENDDEFINE
          *
          *-- EndDefine: basform
          **************************************************
                            


Keywords: kbprb kbcode KB169111