Cancel Property Example

The following example creates a command button and an OptionGroup control and places them on a form. The Cancel property is used to assign the command button as the Cancel button. If the ESC key is pressed, the Command button's Click event occurs and the Click event procedure executes CLEAR EVENTS to close the form and stop event processing.

The OptionGroup control has three buttons; depending on the option button you click, a circle, ellipse, or square is displayed. The Shape Control is used to create the circle, ellipse, and square. The OptionGroup control's Click event uses a DO CASE ... ENDCASE structure and the Value property to display the appropriate shape when you click an option button.

frmMyForm = CREATEOBJECT('Form')  && Create a Form
frmMyForm.Closable = .F.  && Disable the Control menu box 

frmMyForm.AddObject('cmdCommand1','cmdMyCmndBtn')  && Add Command button
frmMyForm.AddObject('opgOptionGroup1','opgMyOptGrp') && Add Option Group
frmMyForm.AddObject('shpCircle1','shpMyCircle')  && Add Circle Shape
frmMyForm.AddObject('shpEllipse1','shpMyEllipse')  && Add Ellipse Shape
frmMyForm.AddObject('shpSquare','shpMySquare')  && Add Box Shape

frmMyForm.cmdCommand1.Visible =.T.  && "Quit" Command button visible

frmMyForm.opgOptionGroup1.Buttons(1).Caption = "\<Circle"
frmMyForm.opgOptionGroup1.Buttons(2).Caption = "\<Ellipse"
frmMyForm.opgOptionGroup1.Buttons(3).Caption = "\<Square"
frmMyForm.opgOptionGroup1.SetAll("Width", 100) && Set Option group width
frmMyForm.opgOptionGroup1.Visible = .T.  && Option Group visible
frmMyForm.opgOptionGroup1.Click  && Show the circle

frmMyForm.SHOW  && Display the form
READ EVENTS  && Start event processing

DEFINE CLASS opgMyOptGrp AS OptionGroup  && Create an Option Group
   ButtonCount = 3  && Three Option buttons
   Top = 10
   Left = 10
   Height = 75
   Width = 100

   PROCEDURE Click 
      ThisForm.shpCircle1.Visible = .F.  && Hide the circle
      ThisForm.shpEllipse1.Visible = .F.  && Hide the ellipse
      ThisForm.shpSquare.Visible = .F.  && Hide the square
      
      DO CASE
         CASE ThisForm.opgOptionGroup1.Value = 1
            ThisForm.shpCircle1.Visible = .T. && Show the circle
         CASE ThisForm.opgOptionGroup1.Value = 2 
            ThisForm.shpEllipse1.Visible = .T.  && Show the ellipse
         CASE ThisForm.opgOptionGroup1.Value = 3 
            ThisForm.shpSquare.Visible = .T.  && Show the square
      ENDCASE
ENDDEFINE

DEFINE CLASS cmdMyCmndBtn AS CommandButton  && Create Command button
   Caption = '\<Quit'  && Caption on the Command button
   Cancel = .T.  && Default Cancel Command button (Esc)
   Left = 125  && Command button column
   Top = 210  && Command button row
   Height = 25  && Command button height

   PROCEDURE Click
      CLEAR EVENTS  && Stop event processing, close Form
ENDDEFINE

DEFINE CLASS shpMyCircle AS SHAPE  && Create a circle
   Top = 10
   Left = 200
   Width = 100
   Height = 100
   Curvature = 99
   BackColor = RGB(255,0,0)  && Red
ENDDEFINE

DEFINE CLASS shpMyEllipse AS SHAPE  && Create an ellipse
   Top = 35
   Left = 200
   Width = 100
   Height = 50
   Curvature = 99
   BackColor = RGB(0,128,0)  && Green
ENDDEFINE

DEFINE CLASS shpMySquare AS SHAPE  && Create a square
   Top = 10
   Left = 200
   Width = 100
   Height = 100
   Curvature = 0
   BackColor = RGB(0,0,255)  && Blue
ENDDEFINE