Text Input with time delay

Question

My scenario: I have built up a form with multiple input fields. One of the text input field has an underlying event listener, which catches up the "change" event.

Private Sub orderID_Change()
    If Not IsNull(Me.orderID.Text) Then
        Set Me.orders.Recordset = ordermanager.getOrder(Me.orderID.Text)
    End If
End Sub

When the user types in an specific order number, the callback runs for each letter/sign the user has already typed into the text field.

My question: Is there a possible solution in msaccess, to create a time delay for a specific input mask?

For example: A user is typing an order number with some digits. When the first change event is fired, an internal timer function starts to decrement a counter. As long as now additional interaction happens with the user, the timer runs out of time and calls the underlying function. If in the meantime, additional input has made by the user, the counter should be reset.

For example: user types in "123"

SYSTEM     : waiting for input
USER INPUT : 1
SYSTEM     : timer 100ms
SYSTEM     : timer 80ms
SYSTEM     : timer 60ms
SYSTEM     : timer 40ms
USER INPUT : 2
SYSTEM     : timer 100ms
SYSTEM     : timer 80ms
USER INPUT : 3
SYSTEM     : timer 100ms
SYSTEM     : timer 80ms
SYSTEM     : timer 60ms
SYSTEM     : timer 40ms
SYSTEM     : timer 20ms
SYSTEM     : timer 0ms
SYSTEM     : Run Routine

Answer 1

Use the form Timer event. Set TimerInterval to zero at form load. Then, in the text box change event, reset TimerInterval to your count-down timer value.

Note Me.orderID.Text is a text property and will never be Null. Therefore check whether its length is greater than zero in orderID_Change.

Private Sub Form_Load()
    Me.TimerInterval = 0
End Sub

Private Sub Form_Timer()
    MsgBox "Run routine now"
    Me.TimerInterval = 0
End Sub

Private Sub orderID_Change()
    'If Not IsNull(Me.orderID.Text) Then
    If Len(Me.orderID.Text) > 0 Then
        Me.TimerInterval = 1000 ' milliseconds
    Else
        Me.TimerInterval = 0
    End If
End Sub

I tested that approach with a sample form in Access 2007 and I think it does what you requested. If you wanted to do something like this for more than one text box on the same form, this suggestion wouldn't cut it.

Answer 2

I would suggest that you use the _AfterUpdate event instead - and just have the user press the enter key, or tab key when finished entering characters. That way it will only fire once. Trying to build a timer may not work either if the user pauses to look for something.

Or if the Order # is always the same length (i.e. 6), you could do:

Private Sub orderID_Change()
    If Len(Me.orderID.Text) < 6 Then
        'Debug.Print "len=" & Len(Me.orderID.Text)
        Exit Sub
    Else
        'Debug.Print "Ready to set RS!!"
        Set Me.orders.Recordset = ordermanager.getOrder(Me.orderID.Text)
    End If
End Sub