The source code in this issue is designed for Visual Basic 5.0 and above. It can be used with some small modifications in VB 3 and 4.
This issue shows how to implement a machine independent delay function.
This routine is useful in your applications where you want to wait a certain number of seconds for input. Some good examples are during communications programs or waiting for input. The Wait function allows you to abort it and determine how many seconds it has already been waiting for.
An interesting aspect of this routine you should notice is that the last two parameters are passed by reference. This means that if the values of these variables change anyplace in your program (in this routine or outside of this routine) they will always reflect the current value. This is how we are able to abort the Wait routine from outside of the actual routine. See the sample below for an implementation of this feature.
Public Function Wait(ByVal lSeconds As Long, _
Optional ByRef bAbortFlag As Boolean = False, _
Optional ByRef lElapsed As Long) As Boolean
True means the function timed out (meaning the number of seconds specified by lSeconds has elapsed). False if the bAbortFlag is set to True.
This example will show how to use the Wait function in a situation where your software is dialing a phone number. It assumes you have a form with two Command Buttons on it (cmdCancel and cmdDial). It also assumes you have a Timer control (tmrStatusUpdate) and a Label control (lblStatus). This example will wait 45 seconds for the call to be completed or aborted.
Dim mbAbortFlag As Boolean ' Used to cancel the delay process
Dim mlElapsed As Long ' Used to track the number of
' elapsed seconds during the pause
Private Sub cmdCancel_Click()
mbAbortFlag = True
End Sub
Private Sub cmdDial_Click()
'
' Dial a phone number....
'
mbAbortFlag = False
If Not Wait(45, mbAbortFlag, mlElapsed) Then
' In this example aborted could mean the connection completed
' or the user cancelled it.
MsgBox "Aborted."
Else
' Abort the dialing process since the timer has elapsed.
MsgBox "Timed out."
End If
End Sub
Private Sub tmrStatusUpdate_Timer()
lblStatus = mlElapsed & " seconds have elapsed."
End Sub
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