How to Place a Timer in the Main Window

• Microsoft Visual FoxPro for Windows, version 3.0

SUMMARY

The Timer control is new to Visual FoxPro. It can execute code at regular intervals and is not a visual control. You can use the timer to periodically execute a set of commands. The following two sample programs illustrate the basic commands to place a timer on the Visual FoxPro version 3.0 desktop.

MORE INFORMATION

Method One: Use the ADDOBJECT() Method to Place the Timer on the Desktop

The _SCREEN system memory variable holds a reference to the main Visual FoxPro window. It allows you to manipulate it as a form. This memory variable will be used in this sample.

The following code places a timer that displays the time. Similar code can be used to place any control on the desktop. Press the F6 key to release the timer.

Place the following code in a program (.PRG) file:

   * To remove the object:
   ON KEY LABEL F6 _SCREEN.RemoveObject('oTime')

   * To activate the Timer:
   _SCREEN.AddObject('oTime','MyTimer')

   * Class definition. The TIMER event is triggered every second, and a
   * WAIT WINDOW is displayed.
   DEFINE CLASS MyTimer AS Timer
      Interval= 1000
      PROCEDURE Timer
        WAIT WINDOW (TIME()) NOWAIT
      ENDPROC
   ENDDEFINE

Method two: Encapsulate the Object in a Container Class

This sample program does the same operations as the first example. The timer is added to a container class, and the CREATEOBJECT() function instantiates the object. To execute the sample, place it in a .PRG file and run the program. Press the F6 key to release the timer.

   PUBLIC oTimerObj

   * The instance variable is released when F6 is pressed.
   ON KEY LABEL f6 RELEASE oTimerObj

   oTimerObj=CREATEOBJECT('MyTimer')

   DEFINE CLASS MyTimer as Container
      ADD OBJECT oTimerobj as TimerClock
   ENDDEFINE

   DEFINE CLASS TimerClock as Timer
      Interval = 1000
      PROCEDURE Timer
         WAIT WINDOW (TIME()) NOWAIT
      ENDPROC
   ENDDEFINE