CheckBox.KeyDown Event (Access)
The KeyDown event occurs when the user presses a key while a form or control has the focus. This event also occurs if you send a keystroke to a form or control by using the SendKeys action in a macro or the SendKeys statement in Visual Basic.
Syntax
expression .KeyDown(KeyCode, Shift)
expression A variable that represents a CheckBox object.
Parameters
Name |
Required/Optional |
Data Type |
Description |
|---|---|---|---|
KeyCode |
Required |
Integer |
A key code, such as vbKeyF1 (the F1 key) or vbKeyHome (the HOME key). To specify key codes, use the intrinsic constants shown in the Object Browser. You can prevent an object from receiving a keystroke by setting KeyCode to 0. |
Shift |
Required |
Integer |
The state of the SHIFT, CTRL, and ALT keys at the time of the event. If you need to test for the Shift argument, you can use one of the following intrinsic constants as bit masks:
|
Remarks
To run a macro or event procedure when these events occur, set the OnKeyDown property to the name of the macro or to [Event Procedure].
For both events, the object with the focus receives all keystrokes. A form can have the focus only if it has no controls or all its visible controls are disabled.
A form will also receive all keyboard events, even those that occur for controls, if you set the KeyPreview property of the form to Yes. With this property setting, all keyboard events occur first for the form, and then for the control that has the focus. You can respond to specific keys pressed in the form, regardless of which control has the focus. For example, you may want the key combination CTRL+X to always perform the same action on a form.
If you press and hold down a key, the KeyDown and KeyPress events alternate repeatedly (KeyDown, KeyPress, KeyDown, KeyPress, and so on) until you release the key, then the KeyUp event occurs.
Although the KeyDown event occurs when most keys are pressed, it is typically used to recognize or distinguish between:
Extended character keys, such as function keys.
Navigation keys, such as HOME, END, PAGE UP, PAGE DOWN, UP ARROW, DOWN ARROW, RIGHT ARROW, LEFT ARROW, and TAB.
Combinations of keys and standard keyboard modifiers (SHIFT, CTRL, or ALT keys).
The numeric keypad and keyboard number keys.
The KeyDown event does not occur when you press:
The ENTER key if the form has a command button for which the Default property is set to Yes.
The ESC key if the form has a command button for which the Cancel property is set to Yes.
The KeyDown event occurs when you press or send an ANSI key. The KeyUp event occurs after any event for a control caused by pressing or sending the key. If a keystroke causes the focus to move from one control to another control, the KeyDown event occurs for the first control, while the KeyPress and KeyUp events occur for the second control.
To find out the ANSI character corresponding to the key pressed, use the KeyPress event.
If a modal dialog box is displayed as a result of pressing or sending a key, the KeyDown and KeyPress events occur, but the KeyUp event doesn't occur.
Example
The following example determines whether you have pressed the SHIFT, CTRL, or ALT key.
To try the example, add the following event procedure to a form containing a text box named KeyHandler.
Private Sub KeyHandler_KeyDown(KeyCode As Integer, _
Shift As Integer)
Dim intShiftDown As Integer, intAltDown As Integer
Dim intCtrlDown As Integer
' Use bit masks to determine which key was pressed.
intShiftDown = (Shift And acShiftMask) > 0
intAltDown = (Shift And acAltMask) > 0
intCtrlDown = (Shift And acCtrlMask) > 0
' Display message telling user which key was pressed.
If intShiftDown Then MsgBox "You pressed the SHIFT key."
If intAltDown Then MsgBox "You pressed the ALT key."
If intCtrlDown Then MsgBox "You pressed the CTRL key."
End Sub