Explanation & Usage of the LOCKSCREEN Property

ID: Q129413

3.00 WINDOWS kbprg

The information in this article applies to:

Microsoft Visual FoxPro for Windows, version 3.0

SUMMARY

Visual FoxPro forms support a special form property called LOCKSCREEN. This property is used to govern the behavior of a screen including how and when it updates when an event such as a color change occurs.

MORE INFORMATION

The LOCKSCREEN property is explained as follows in the online Help:

   The LOCKSCREEN property determines whether a Form batches all changes to
   property settings on the Form and its contained objects.

   Syntax:

   Form.LockScreen[ = lExpr]

   Settings:

   lExpr

   The settings for the LockScreen property are:

   Setting      Description
   --------------------------------------------------------------------
   True (.T.)   The Form and its contained objects reflect changes in
                property settings in batch mode, or all at once, rather
                than as soon as the changes are made.

   False (.F.)  (Default) The Form and its contained objects reflect
                changes in property settings as soon as the changes are
                made.

   Remarks:

   Available at design time and run time.

   Set LockScreen to true (.T.) to reduce annoying screen refreshes when
   presentation properties such as BackColor, FontName, and so on are
   changed during run time.

   NOTE: If you set LockScreen to false (.F.), the Form and all its
   controls are repainted.

The LOCKSCREEN property is found on the Layout tab of the Form Properties sheet. As noted, the default for this property is false, which means that as soon as a change is made to a form or its objects, as in the following, the change will be immediately reflected on the form:

Form1.BackColor=RGB(150,0,200)

If the LOCKSCREEN property is set to true, the previous command will not be reflected until such time as you issue a command like this:

FORM1.REFRESH

-or-

FORM1.PAINT

The key advantage to you as a programmer is that you can make a series of changes to an object such as a screen without having each item flicker and update to reflect the new changes you've made. Instead, you can turn this property off, make your changes, and then force a refresh of the screen for a much crisper and more professional appearance.

Additional reference words: 3.00 VFoxWin Screen Update Refresh KBCategory: kbprg KBSubcategory: FxprgGeneral

Keywords          : FxprgGeneral 
Version           : 3.00
Platform          : WINDOWS