ON KEY LABEL Command

Specifies a command that executes when you press a specific key or key combination or click the mouse button.

ON KEY [LABEL KeyLabelName] [Command]

Parameters

• LABEL KeyLabelName
  Specifies the key label name assigned to the key. The KeyLabelName is the letter or digit on the key or a special name assigned to the key. The following table lists the special key label names.

  Visual FoxPro key label assignments

  For this key	Specify this KeyLabelName value
  	LEFTARROW
  	RIGHTARROW
  	UPARROW
  	DNARROW
  HOME	HOME
  END	END
  PAGE UP	PGUP
  PAGE DOWN	PGDN
  DEL	DEL
  BACKSPACE	BACKSPACE
  SPACEBAR	SPACEBAR
  INS	INS
  TAB	TAB
  SHIFT+TAB	BACKTAB
  Left Brace	LBRACE
  Right Brace	RBRACE
  ENTER	ENTER
  F1 to F12	F1, F2, F3 ...
  CTRL+F1 to CTRL+F12	CTRL+F1, CTRL+F2 ...
  SHIFT+F1 to SHIFT+F12	SHIFT+F1, SHIFT+F2 ...
  ALT+F1 to ALT+F12	ALT+F1, ALT+F2, ALT+F3 ...
  ALT+0 to ALT+9	ALT+0, ALT+1, ALT+2 ...
  ALT+A to ALT+Z	ALT+A, ALT+B, ALT+C ...
  CTRL+LEFT ARROW	CTRL+LEFTARROW
  CTRL+RIGHT ARROW	CTRL+RIGHTARROW
  CTRL+HOME	CTRL+HOME
  CTRL+END	CTRL+END
  CTRL+PAGE UP	CTRL+PGUP
  CTRL+PAGE DOWN	CTRL+PGDN
  CTRL+A TO CTRL+Z	CTRL+A, CTRL+B, CTRL+C ...
  CTRL+0	CTRL+0
  RIGHT MOUSE BUTTON	RIGHTMOUSE
  LEFT MOUSE BUTTON	LEFTMOUSE
  MOUSE BUTTON	MOUSE
  ESC	ESC

• Command
  Specifies the command that executes when you press the specified key or key combination or click the mouse button.

  You can include parameter or parameter expressions with the command that you assign to the key, as in the following example:

  ON KEY LABEL ALT+V WAIT WINDOW "Version: " + VERSION()
  

  You can include variables in the assignment, but they must be public. For example:

  PUBLIC message
  message = "Default drive: " + SYS(5)
  ON KEY LABEL ALT+D WAIT WINDOW message
  

Remarks

ON KEY LABEL typically uses DO to execute a procedure.

ON KEY LABEL executes the command immediately during the execution of READ, BROWSE, EDIT, CHANGE, and user-defined menus. If a program is executing when you press the key or click the mouse button, Visual FoxPro executes the current program line and then executes the ON KEY LABEL command. Any ON KEY LABEL key assignments created in a program remain in effect after the program is run. You can also create key assignments in the Command window.

To restore the behavior of a specific key to normal, issue ON KEY LABEL KeyLabelName. To restore all keys to their default behavior, issue ON KEY.

The ON KEY LABEL key assignments aren't in effect in the Visual FoxPro system menu bar, system menus, dialog boxes, alerts, and so on. The key assignments are effective in the Visual FoxPro system windows — the Visual FoxPro text editor, the Command window, the Trace window, and so on.

Unlike ON KEY, there can be multiple active ON KEY LABEL commands. For example, you can assign a command to each of the arrow keys and a mouse button.

Executing an ON KEY LABEL resets PARAMETERS( ) to 0. For more information, see PARAMETERS( ) Function.

In Visual FoxPro, certain events cannot be trapped because they are under the control of Windows. In particular, ON KEY LABEL MOUSE, ON KEY LABEL LEFTMOUSE, and ON KEY LABEL RIGHTMOUSE are not executed when you click a Windows control such as a Control menu, scroll bar, or the like. Also, CTRL+0 is supported in ON KEY LABEL in Visual FoxPro, allowing you to redefine the key combination used to enter a null value into a field.

Note that ON KEY LABEL operates outside of the scope of a form; the KeyPress event can be used within forms to execute code when a key is pressed.

Example

The following example displays a message when an arrow key is pressed.

CLEAR
PUBLIC msg
msg = CHR(13) + CHR(13) + "Press F9 to " + ;
   "restore default key definition."
ON KEY LABEL RIGHTARROW Wait Window "Right Arrow " + msg NOWAIT
ON KEY LABEL LEFTARROW Wait Window "Left Arrow " + msg NOWAIT
ON KEY LABEL UPARROW Wait Window "Up Arrow " + msg NOWAIT
ON KEY LABEL DNARROW Wait Window "Down Arrow " + msg NOWAIT

* Press F9 to clear the ON KEY LABEL assignments
ON KEY LABEL F9 ON KEY

See Also

Reference

INKEY( ) Function
KeyPress Event
ON( ) Function
POP KEY Command
PUSH KEY Command

Other Resources

Commands (Visual FoxPro)