Programming Forums > Application Development > Visual Basic

hipolito · Apr 8th, 2005, 12:57 PM

Hello all,

I have done an application TESTE.EXE using VB 6.0, but every time I click on the file the application opens, like it should, but even if it is already open...

What do I do for the application just pops back up when it is minimised and I click on the TESTE.EXE again???

Thx in advance.

Rory · Apr 8th, 2005, 2:02 PM

I assume what you mean is restricting use to one instance of the app, and giving focus to the existent instance if another copy is run.
The VB way of doing this would be:

(Toggle Plain Text)

Sub Main()
If App.PrevInstance Then
    VBA.AppActivate App.Title, 0
Else
    Form1.Show
End If
End Sub

Unfortunately that doesn't work (it doesn't bring focus back to the application. Try this in your sub main: it uses an API method to find the handle of the active window of the previous instance and give focus to it. Obviously your app must have a window!

(Toggle Plain Text)

Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Public Declare Function GetWindow Lib "user32" (ByVal Hwnd As Long, ByVal wCmd As Long) As Long
Public Declare Function OpenIcon Lib "user32" (ByVal Hwnd As Long) As Long
Public Declare Function SetForegroundWindow Lib "user32" (ByVal Hwnd As Long) As Long

Sub Main()
    If App.PrevInstance Then
        FocusPrevInstance
    Else
        Form1.Show
    End If
End Sub

Private Sub FocusPrevInstance()
Dim ThisObject As String
Dim ObjHwnd As Long

ThisObject = App.Title
App.Title = "_" & App.Title 'rename this instance so we don't find ourselves!

 ' Find runnning instance's application object, trying various class names
ObjHwnd = FindWindow("ThunderRTMain", ThisObject)
If ObjHwnd = 0 Then ObjHwnd = FindWindow("ThunderRT5Main", ThisObject)
If ObjHwnd = 0 Then ObjHwnd = FindWindow("ThunderRT6Main", ThisObject)

ObjHwnd = GetWindow(ObjHwnd, &H3) ' Get active window

hFocusWnd ObjHwnd

End Sub

Private Sub hFocusWnd(ByVal Hwnd As Long) 'Focuses specified window
    OpenIcon Hwnd
    SetForegroundWindow Hwnd
End Sub

drruggy · Apr 14th, 2005, 6:09 PM

(Toggle Plain Text)

If App.PrevInstance Then
        Unload Me
        End
    End If

hipolito · Apr 15th, 2005, 7:02 AM

Quote:

Originally Posted by drruggy

(Toggle Plain Text)

If App.PrevInstance Then
        Unload Me
        End
    End If

didnt work too....

:-(

Rory · Apr 15th, 2005, 1:17 PM

I'm very suprised: re my second code block are you sure you've copied it in its entirity into a Module (.bas) and have set the startup mode of the project to sub main?

hipolito · Apr 20th, 2005, 3:54 PM

Quote:

Originally Posted by Rory

I'm very suprised: re my second code block are you sure you've copied it in its entirity into a Module (.bas) and have set the startup mode of the project to sub main?

Hey rory, thx man, yes it did work just fine, great work man..

Thank you.

Rory · Apr 21st, 2005, 11:55 AM

No probs!

Apr 8th, 2005, 12:57 PM	#1
hipolito Programmer Join Date: Feb 2005 Posts: 41 Rep Power: 0	Application opens twice ! Hello all, I have done an application TESTE.EXE using VB 6.0, but every time I click on the file the application opens, like it should, but even if it is already open... What do I do for the application just pops back up when it is minimised and I click on the TESTE.EXE again??? Thx in advance.

Apr 8th, 2005, 2:02 PM	#2
Rory Expert Programmer Join Date: Jan 2005 Location: London Posts: 542 Rep Power: 4	I assume what you mean is restricting use to one instance of the app, and giving focus to the existent instance if another copy is run. The VB way of doing this would be: (Toggle Plain Text) Sub Main() If App.PrevInstance Then VBA.AppActivate App.Title, 0 Else Form1.Show End If End Sub Sub Main() If App.PrevInstance Then VBA.AppActivate App.Title, 0 Else Form1.Show End If End Sub Unfortunately that doesn't work (it doesn't bring focus back to the application. Try this in your sub main: it uses an API method to find the handle of the active window of the previous instance and give focus to it. Obviously your app must have a window! (Toggle Plain Text) Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long Public Declare Function GetWindow Lib "user32" (ByVal Hwnd As Long, ByVal wCmd As Long) As Long Public Declare Function OpenIcon Lib "user32" (ByVal Hwnd As Long) As Long Public Declare Function SetForegroundWindow Lib "user32" (ByVal Hwnd As Long) As Long Sub Main() If App.PrevInstance Then FocusPrevInstance Else Form1.Show End If End Sub Private Sub FocusPrevInstance() Dim ThisObject As String Dim ObjHwnd As Long ThisObject = App.Title App.Title = "_" & App.Title 'rename this instance so we don't find ourselves! ' Find runnning instance's application object, trying various class names ObjHwnd = FindWindow("ThunderRTMain", ThisObject) If ObjHwnd = 0 Then ObjHwnd = FindWindow("ThunderRT5Main", ThisObject) If ObjHwnd = 0 Then ObjHwnd = FindWindow("ThunderRT6Main", ThisObject) ObjHwnd = GetWindow(ObjHwnd, &H3) ' Get active window hFocusWnd ObjHwnd End Sub Private Sub hFocusWnd(ByVal Hwnd As Long) 'Focuses specified window OpenIcon Hwnd SetForegroundWindow Hwnd End Sub Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long Public Declare Function GetWindow Lib "user32" (ByVal Hwnd As Long, ByVal wCmd As Long) As Long Public Declare Function OpenIcon Lib "user32" (ByVal Hwnd As Long) As Long Public Declare Function SetForegroundWindow Lib "user32" (ByVal Hwnd As Long) As Long Sub Main() If App.PrevInstance Then FocusPrevInstance Else Form1.Show End If End Sub Private Sub FocusPrevInstance() Dim ThisObject As String Dim ObjHwnd As Long ThisObject = App.Title App.Title = "_" & App.Title 'rename this instance so we don't find ourselves! ' Find runnning instance's application object, trying various class names ObjHwnd = FindWindow("ThunderRTMain", ThisObject) If ObjHwnd = 0 Then ObjHwnd = FindWindow("ThunderRT5Main", ThisObject) If ObjHwnd = 0 Then ObjHwnd = FindWindow("ThunderRT6Main", ThisObject) ObjHwnd = GetWindow(ObjHwnd, &H3) ' Get active window hFocusWnd ObjHwnd End Sub Private Sub hFocusWnd(ByVal Hwnd As Long) 'Focuses specified window OpenIcon Hwnd SetForegroundWindow Hwnd End Sub

Apr 14th, 2005, 6:09 PM	#3
drruggy Newbie Join Date: Apr 2005 Posts: 19 Rep Power: 0	(Toggle Plain Text) If App.PrevInstance Then Unload Me End End If If App.PrevInstance Then Unload Me End End If

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Apr 15th, 2005, 1:17 PM	#5
Rory Expert Programmer Join Date: Jan 2005 Location: London Posts: 542 Rep Power: 4	I'm very suprised: re my second code block are you sure you've copied it in its entirity into a Module (.bas) and have set the startup mode of the project to sub main?

Apr 21st, 2005, 11:55 AM	#7
Rory Expert Programmer Join Date: Jan 2005 Location: London Posts: 542 Rep Power: 4	No probs!

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Programming Forums > Application Development > Visual Basic

Application opens twice !