 This
is pretty close to the minimum code required to flash an application's
window or taskbar via the FlashWindow API using VB's
intrinsic Timer control.
Flashing a window means changing the appearance of its caption bar as if
the window were changing from inactive to active status, or vice versa.
(An inactive caption bar changes to an active caption bar; an active
caption bar changes to an inactive caption bar.) Typically, a window is
flashed to inform the user that the window requires attention but that it
does not currently have the keyboard focus. The FlashWindow function
flashes the window only once; for repeated flashing, the application
requires calling via a VB or system timer.
When FlashWindow's bInvert parameter is TRUE, the window is flashed from
one state to the other. If it is FALSE, the window is returned to its
original state (either active or inactive). When an application is
minimized and this parameter is TRUE, the taskbar window button flashes
active/inactive. If it is FALSE, the taskbar window button flashes
inactive, meaning that it does not change colors. It flashes, as if it
were being redrawn, but it does not provide the visual invert clue to the
user.
With SetTimer, the nIDEvent member specifies a non-zero timer identifier.
If the hwnd parameter of SetTimer is null, nIDEvent is ignored. If hwnd
is non-null and the window specified by hwnd already has a timer with the
value nIDEvent, then the existing timer is replaced by the new timer.
When SetTimer replaces a timer, the timer is reset. Therefore, a message
will be sent after the current time-out value elapses, but the previously
set time-out value is ignored. The hwnd parameter specifies the
handle to the window to be associated with the timer --- this window must
be owned by the calling thread. If this parameter is null (0&) no
window is associated with the timer and the nIDEvent parameter is
ignored. |
Option Explicit
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Copyright ©1996-2011 VBnet/Randy Birch, All Rights Reserved.
' Some pages may also contain other copyrights by the author.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Distribution: You can freely use this code in your own
' applications, but you may not reproduce
' or publish this code on any web site,
' online service, or distribute as source
' on any media without express permission.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Private Declare Function FlashWindow Lib "user32" _
(ByVal hwnd As Long, _
ByVal bInvert As Long) As Long
Private Sub Form_Load()
With Combo1
.AddItem "50"
.AddItem "100"
.AddItem "250"
.AddItem "500"
.AddItem "1000"
.ListIndex = 2
End With
Command1.Caption = "Begin Flash"
Command2.Caption = "Stop Flash"
Timer1.Enabled = False
End Sub
Private Sub Command1_Click()
Call FlashBegin(Me.hwnd, Val(Combo1.List(Combo1.ListIndex)))
Combo1.Enabled = False
Command1.Enabled = False
End Sub
Private Sub Command2_Click()
Call FlashEnd(Me.hwnd)
Command1.Enabled = True
Combo1.Enabled = True
End Sub
Private Sub FlashBegin(ByVal hwnd As Long, ByVal Frequency As Long)
If Timer1.Enabled = False Then
If Frequency > 0 Then
Timer1.Interval = Frequency
Timer1.Enabled = True
End If
End If
End Sub
Private Sub FlashEnd(ByVal hwnd As Long)
If Timer1.Enabled Then
Call FlashWindow(hwnd, False)
Timer1.Enabled = False
End If
End Sub
Private Sub Timer1_Timer()
Call FlashWindow(hwnd, True)
End Sub |
