However, BackSpace does trigger KeyPress. The KeyDown and KeyUp events let you manage those. Non-text keystrokes (such as Tab, Enter, PgDn, Home, Del, Alt, Esc) do not trigger the KeyPress event. If Access happens to be in Over-Type mode and the cursor is in the middle of the text, a character is automatically selected so over-type still works. If any characters are selected, they are replaced when a character is typed, so we subtract the length of the selection (its SelLength property). " reads the number of characters already in the text box (its Text property). The middle line of this procedure does this, after checking two conditions. Setting KeyAscii to zero destroys the keystroke before it reaches the text box. When a user types a character into the control, KeyPress is triggered.
How Do These Procedures Work? LimitKeyPress() Block unacceptable keystrokes in the KeyPress event before they reach the control, and truncate entries in the Change event if the user pastes in too much text. However, this event alone is inadequate: a user can paste text into the control without firing the KeyPress, KeyDown, or KeyUp events. You can simply discard unacceptable keystrokes, leaving the text in the control as it was. The KeyPress event does not have these problems.
MICROSOFT ACCESS DATABASE SIZE LIMIT UPDATE
However, maintaining such a variable would be a nightmare: can you guarantee to initialize every variable to the control's DefaultValue in the form's Load event, update its variable on every occasion that a control is written to programmatically, effectively document this to ensure no other programmer writes to the control without updating the variable, etc.? You could create a variable for each control, store its last known good entry, and restore that value if the Change event finds the text is too long. There is no way to retrieve the last acceptable entry if it's too long. When the Change event fires, the text is already in the control.
Repeat steps 2 and 3 for other unbound text/combo boxes in your application.For the same example, the Change event procedure is: Call LimitChange() in your text box's Change event.For example, to limit a control named "City" to 40 characters, its KeyPress event procedure is:Ĭall LimitKeyPress(Me.City, 40, KeyAscii) Call LimitKeyPress() in your text box's KeyPress event.
Paste the two "subs" from the end of this article into a module.However, the input mask has side effects such as appending underscores to the Text property and making it difficult to insert text into the middle of an entry.įor a cleaner result, use a combination of the control's KeyPress and Change events. Unbound controls can be limited with the Input Mask - one "C" for each possible character. Microsoft Access tips: Unbound text box: limiting entry length Microsoft Access Tips for Serious UsersĪccess automatically prevents you entering too much text if a control is bound to a field.
0 kommentar(er)
