How to switch to another application from mine

If you know the window handle, you can use the SetActiveWindow() SetForegroundWindow method to do this. You'll need to include it from user32.dll

Declare Function SetActiveWindow SetForegroundWindow Lib "user32" (ByVal hwnd As Integer) As Integer

From your code

SetActiveWindow SetForegroundWindow(hwnd)

I haven't tested this, but I'm pretty sure it will do the trick.

Regards,

<Corrected>

SvenDeBont at 2007-10-2 >

ahmedilyas wrote:

you could also use the SetForegroundWindow API, I think they both do the same job

Thanks for pointing that out.. you should use the SetForegroundWindow to activate another application. SetActiveWindow only works for applications in the foreground. My mistake.

SvenDeBont at 2007-10-2 >

ahmedilyas wrote:

:-) Glad we shared and learned something from each other - that's what it's about! http://www.pinvoke.net/default.aspx/user32/SetForegroundWindow.html Sample here on how to implement the API: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=611602&SiteID=1

Tried the above and it works...Except...the application I am trying to bring to the front can be minimised to the system tray, when it is it will not come to the front. Anyone know how to get round this.

Thanks.

Rabtok at 2007-10-2 >

Sven De Bont wrote:

You can use the ShowWindow API for this <DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _ Private Function ShowWindow(ByVal hwnd As IntPtr, ByVal nCmdShow As Int32) As Long To restore a window, use the value 9 from your code ShowWindow(hwnd, 9) See http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/WindowsUserInterface/Windowing/Windows/WindowReference/WindowFunctions/ShowWindow.asp for an explantion and possible values for the nCmdShow parameter. Regards,

Many thanks. However it leaves the program so called (iTunes in this case) unable to use menus or system min/max buttons, you can only use keyboard Alt+key to select them. tried a few values other than 9.

Any one experienced this.

Final working code:

Public Enum ShowWindowConstants
SW_HIDE = 0
SW_SHOWNORMAL = 1
SW_NORMAL = 1
SW_SHOWMINIMIZED = 2
SW_SHOWMAXIMIZED = 3
SW_MAXIMIZE = 3
SW_SHOWNOACTIVATE = 4
SW_SHOW = 5
SW_MINIMIZE = 6
SW_SHOWMINNOACTIVE = 7
SW_SHOWNA = 8
SW_RESTORE = 9
SW_SHOWDEFAULT = 10
SW_FORCEMINIMIZE = 11
SW_MAX = 11
End Enum

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function FindWindow(ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr
End Function
<DllImport("user32.dll", SetLastError:=True)> _
Private Shared Function SetForegroundWindow(ByVal hWnd As IntPtr) As Boolean
End Function
<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function SetActiveWindow(ByVal hWnd As IntPtr) As IntPtr
End Function
Declare Sub SwitchToThisWindow Lib "user32.dll" (ByVal hWnd As IntPtr, ByVal fAltTab As Boolean)
Declare Function ShowWindow Lib "user32.dll" (ByVal hwnd As IntPtr, ByVal nCmdShow As Int32) As Long
<DllImport("User32.dll")> _
Public Shared Function ShowWindowAsync(ByVal hWnd As IntPtr, ByVal swCommand As Integer) As Integer
End Function
<DllImport("user32.dll", SetLastError:=True)> _
Private Shared Function IsWindowVisible(ByVal hwnd As IntPtr) As Boolean
End Function

Private Sub bnSwitch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnSwitch.Click
Dim hwnd As Integer

hwnd = FindWindow(Nothing, "iTunes")

If hwnd > 0 Then
If IsWindowVisible(hwnd) = False Then
ShowWindowAsync(hwnd, ShowWindowConstants.SW_MAXIMIZE)
End If

SwitchToThisWindow(hwnd, True)
REM SetForegroundWindow(hwnd)
REM SetActiveWindow(hwnd)
End If
end sub

Rabtok at 2007-10-2 >

Sven De Bont wrote:

If your code is working, could you mark the reply as 'answer' so the thread appears as solved to other users? Thanks,

Rabtok at 2007-10-2 >

Answer:

Dim MusicProc As New Process

MusicProc.StartInfo.FileName = "C:\Program Files\iTunes\iTunes.exe"
MusicProc.StartInfo.WindowStyle = ProcessWindowStyle.Normal
MusicProc.Start()

The other methods are flawed in that they "damage" the running application. I would still like to know what is wrong and what fixes it but will concede the answer as it stands above.

Rabtok at 2007-10-2 >