The following example demonstrates how the Closable property is set to false (.F.) to prevent a form from being closed using the window pop-up menu or the Close button. If the form's Closable property is set to true (.T.) and the form is closed using the window pop-up menu, CLEAR EVENTS must be issued to stop event processing and exit the program.
frmMyForm = CREATEOBJECT('Form') && Create a Form
frmMyForm.Closable = .F. && Disable the window pop-up menu
&& and Close button
frmMyForm.AddObject('shpLine','Line') && Add a Line control to the form
frmMyForm.AddObject('cmdCmndBtn1','cmdMyCmndBtn1') && Up Cmnd button
frmMyForm.AddObject('cmdCmndBtn2','cmdMyCmndBtn2') && Down Cmnd button
frmMyForm.AddObject('cmdCmndBtn3','cmdMyCmndBtn3') && Quit Cmnd button
frmMyForm.shpLine.Visible = .T. && Make Line control visible
frmMyForm.shpLine.Top = 20 && Specify Line control row
frmMyForm.shpLine.Left = 125 && Specify Line control column
frmMyForm.cmdCmndBtn1.Visible =.T. && Up Command button visible
frmMyForm.cmdCmndBtn2.Visible =.T. && Down" Command button visible
frmMyForm.cmdCmndBtn3.Visible =.T. && Quit Command button visible
frmMyForm.SHOW && Display the form
READ EVENTS && Start event processing
DEFINE CLASS cmdMyCmndBtn1 AS COMMANDBUTTON && Create Command button
Caption = 'Slant \<Up' && Caption on the Command button
Left = 50 && Command button column
Top = 100 && Command button row
Height = 25 && Command button height
PROCEDURE Click
ThisForm.shpLine.Visible = .F. && Hide the Line control
ThisForm.shpLine.LineSlant ='/' && Slant up
ThisForm.shpLine.Visible = .T. && Show the Line control
ENDDEFINE
DEFINE CLASS cmdMyCmndBtn2 AS CommandButton && Create Command button
Caption = 'Slant \<Down' && Caption on the Command button
Left = 200 && Command button column
Top = 100 && Command button row
Height = 25 && Command button height
PROCEDURE Click
ThisForm.shpLine.Visible = .F. && Hide the Line control
ThisForm.shpLine.LineSlant ='\' && Slant down
ThisForm.shpLine.Visible = .T. && Show the Line control
ENDDEFINE
DEFINE CLASS cmdMyCmndBtn3 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 = 150 && Command button row
Height = 25 && Command button height
PROCEDURE Click
CLEAR EVENTS && Stop event processing, close Form
ENDDEFINE