How to Use a KeyPress Event in Lieu of ON KEY LABEL

ID: Q140296

The information in this article applies to:

Microsoft Visual FoxPro for Windows, version 3.0

SUMMARY

Many developers use ON KEY LABEL to assign programs or procedures within programs that are to be executed upon pressing a specific key (usually a function key). However, if the ON KEY LABEL assignment is to be specific to a control within a form, a better alternative would be to use the KeyPress event of that control.

MORE INFORMATION

The KeyPress event is available for the following form controls:

CheckBox, ComboBox, CommandButton, EditBox, Form, ListBox, OptionButton, Spinner, TextBox

It is possible to use this event to check for the press of a specific key. When using the KeyPress event to perform an action based on a function key, the function key's value should be used as shown in this table:


   Key     Alone   Shift    Ctrl    Alt
   ------------------------------------
   F1        28      84      94     104
   F2        -1      85      95     105
   F3        -2      86      96     106
   F4        -3      87      97     107
   F5        -4      88      98     108
   F6        -5      89      99     109
   F7        -6      90     100     110
   F8        -7      91     101     111
   F9        -8      92     102     112
   F10       -9      93     103     113
   F11      133     135     137     139
   F12      134     136     138     140

For more information on key values, refer to the INKEY() function in Visual FoxPro Help file.

Step-by-Step Example

The following steps show how to use the KeyPress event.

Create a form, and place a text box on it.

In the ControlSource property of the text box, type mykey (or any other variable that you might prefer).

Place the following code in the KeyPress event of the text box: LPARAMETERS nKeyCode, nShiftAltCtrl *: The previous line of code is already contained in the KeyPress event *: by default. DO CASE CASE nKeyCode = 28 WAIT WINDOW "The F1 Key has been pressed" NOWAIT mykey = "F1 Key" ThisForm.Refresh CASE nKeyCode = -4 WAIT WINDOW "The F5 Key has been pressed" NOWAIT mykey = "F5 Key" ThisForm.Refresh ENDCASE

Place the following code in the Load event of the form: CLEAR MACROS SET HELP OFF *: This will disable FoxPro's default function key assignments.

Place the following code in the Destroy event of the form: RESTORE MACROS SET HELP ON *: This will restore FoxPro's default function key assignments.

Place a command button on the form, and place the following code in its click event: ThisForm.Release

Save and run the form. If either the F1 or F5 key is pressed, the appropriate WAIT WINDOW messages should appear, and the text box should be updated.

Additional query words: VFoxWin

Keywords : kbcode FxprgGeneral
Version : 3.00
Platform : WINDOWS
Issue type :