Mencegah Aplikasi Dijalankan Dua Kali

Di bawah ini merupakan fungsi kedua masih mengenai cara mencegah aplikasi dijalankan dua kali. Bagaimana implementasinya dalam Visual Basic 6.0? bisa Anda simak kodenya di bawah ini:

Option Explicit 
 
Declare Function OpenIcon Lib "user32" (ByVal hWnd As Long) As Long 
Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long 
Declare Function GetWindow Lib "user32" (ByVal hWnd As Long, ByVal wCmd As Long) As Long 
Declare Function SetForegroundWindow Lib "user32" (ByVal hWnd As Long) As Long 
 
Public Const GW_HWNDPREV = 3 
 
Sub ActivatePrevInstance() 
 
    Dim AppTitle As String 
    Dim PrevHndl As Long 
    Dim result As Long 
 
    AppTitle = App.Title 
    App.Title = "unwanted instance" 
 
    If PrevHndl = 0 Then 
        PrevHndl = FindWindow("ThunderRT6Main", AppTitle) 
        If PrevHndl <> 0 Then 
            PrevHndl = GetWindow(PrevHndl, GW_HWNDPREV) 
            result = OpenIcon(PrevHndl) 
            result = SetForegroundWindow(PrevHndl) 
            End 
        End If 
    End If 
 
End Sub 

Contoh penggunaan:

Private Sub Form_Load() 
    If App.PrevInstance Then ActivatePrevInstance 
End Sub