ShowWindow doesn't work

[Sathyaish]

Just that a call to the ShowWindow function is not working as it should.

I have an application and a picture box on it, on the click event of which, as seen below, I trigger another EXE called "Workflow Designer.exe". But if Workflow Designer is already running then I wish only to maximize its window and do not wish to start another instance of it. I have written the code already. It works fine when Workflow Designer is not running any previous instances. However, if Workflow Designer is already running, even then everything works fine except the call to the ShowWindow function.

The ShowWindow function returns 0, as it must if the window is already visible says the documentation, but even then it does not maximize the Workflow Designer Window.

Public Sub picWF_Click(Index As Integer)

Dim hWndWorkflowDesigner As Long
Dim LngRetVal As Long
    If Not BoolToolBarWorkflow Then Exit Sub
    
    mdiNew.WindowState = vbMinimized
    If IsProcessRunning(LngProcessIDWorkflowDesigner) Then
        hWndWorkflowDesigner = GethWndFromProcessID(LngProcessIDWorkflowDesigner)
        If hWndWorkflowDesigner <> 0 Then
            LngRetVal = ShowWindow(hWndWorkflowDesigner, SW_MAXIMIZE)
            If LngRetVal = 0 Then
                Debug.Print Err.LastDllError
            End If
        End If
    Else
        LngProcessIDWorkflowDesigner = Shell(App.Path & "\Workflow Designer.exe", vbMaximizedFocus)
    End If
    
End Sub

In a global module

Public LngProcessIDWorkflowDesigner As Long

Public Function IsProcessRunning(ByVal ProcessID As Long) As Boolean
    IsProcessRunning = (OpenProcess(&H100000, False, ProcessID) <> 0)
End Function

[Pinky98]

ShowWindow does not bring the window to the foreground. It only makes an invisible window visible.

You want to use the MOVEWINDOW API. (Then change the Z order)

[Sathyaish]

I actually did try the SetForeground Window prior to ShowWindow but that too did not work for me. How else do I maximize this window?

[Sathyaish]

Nope! MoveWindow doesn't work either. Lemme try SetWindowPos or BringWindowToTop. Yeah! I remember using BringWindowToTop. That must work here.

Public Sub picWF_Click(Index As Integer)

Dim hWndWorkflowDesigner As Long
Dim LngRetVal As Long
Dim Arr() As String

    If Not BoolToolBarWorkflow Then Exit Sub
    mdiNew.WindowState = vbMinimized
    If IsProcessRunning(LngProcessIDWorkflowDesigner) Then
        hWndWorkflowDesigner = GethWndFromProcessID(LngProcessIDWorkflowDesigner)
        If hWndWorkflowDesigner <> 0 Then
            Arr = Split(GetScreenResolution, "x")
            LngRetVal = MoveWindow(hWndWorkflowDesigner, 0, 0, CLng(Arr(0)), CLng(Arr(1)), False)
            LngRetVal = SetForegroundWindow(hWndWorkflowDesigner)
            If LngRetVal = 0 Then
                Debug.Print Err.LastDllError
            End If
        End If
    Else
        LngProcessIDWorkflowDesigner = Shell(App.Path & "\Workflow Designer.exe", vbMaximizedFocus)
    End If
    
End Sub

[Sathyaish]

Darn! I tried SetwindowPos, BringWindowToTop, SetForegroundWindow, MoveWindow, ShowWindow...bah..none of them worked for me. Please help me out.

[Sathyaish]

Guys, this is crazy. I scratched my head hard and even sent a WM_SIZE to that window but that window won't budge from there.

Public Sub picWF_Click(Index As Integer)

Dim hWndWorkflowDesigner As Long
Dim LngRetVal As Long

    If Not BoolToolBarWorkflow Then Exit Sub
    mdiNew.WindowState = vbMinimized
    If IsProcessRunning(LngProcessIDWorkflowDesigner) Then
        hWndWorkflowDesigner = GethWndFromProcessID(LngProcessIDWorkflowDesigner)
        If hWndWorkflowDesigner <> 0 Then
            LngRetVal = SendMessage(hWndWorkflowDesigner, WM_SIZE, SIZE_MAXIMIZED, 0&)
        End If
    Else
        LngProcessIDWorkflowDesigner = Shell(App.Path & "\Workflow Designer.exe", vbMaximizedFocus)
    End If
    
End Sub

Please help me, please.

[Tinbum747]

Have you tried using AppActivate?

From memory, it uses the Window Caption or a ProcessID rather than the window handle, but you should be able to obtain either of those if you know the window handle.

Hope this helps.

Cheers,
Tinbum747

[Ungi]

Use SetWindowPos API!

Public Const SWP_NOMOVE = 2
Public Const SWP_NOSIZE = 1
Public Const FLAGS = SWP_NOMOVE Or SWP_NOSIZE
Public Const HWND_TOPMOST = -1
Public Const HWND_NOTOPMOST = -2

Declare Function SetWindowPos Lib "USER32" _
            (ByVal hWnd As Long, ByVal hWndInsertAfter As Long, _
            ByVal x As Long, ByVal y As Long, _
            ByVal cx As Long, ByVal cy As Long, _
            ByVal wFlags As Long) As Long

Public Function SetTopMostWindow(hWnd As Long, Topmost As Boolean) As Long
   If Topmost = True Then 'Make the window topmost
      SetTopMostWindow = SetWindowPos(hWnd, HWND_TOPMOST, 0, 0, 0, 0, FLAGS)
   Else
      SetTopMostWindow = SetWindowPos(hWnd, HWND_NOTOPMOST, 0, 0, 0, 0, FLAGS)
      SetTopMostWindow = False
   End If
End Function

If it doesn't work, you possible get the false Windowhandle! You get the correct with this function:

Private Declare Function FindWindow Lib "user32"  Alias "FindWindowA" _
    (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function GetParent Lib "user32" _
    (ByVal hWnd As Long) As Long
Private Declare Function GetWindowThreadProcessId Lib "user32" _
    (ByVal hWnd As Long, lpdwprocessid As Long) As Long
Private Declare Function GetWindow Lib "user32" _   
 (ByVal hWnd As Long, ByVal wCmd As Long) As Long


Private Function GetWinHandle(hInstance As Long) As Long
'returns the belonging windowhandle to the instancehandle
   Dim tempHwnd As Long
   
   ' Grab the first window handle that Windows finds:
   tempHwnd = FindWindow(vbNullString, vbNullString)
   
   ' Loop until you find a match or there are no more window handles:
   Do Until tempHwnd = 0
      ' Check if no parent for this window
      If GetParent(tempHwnd) = 0 Then
         ' Check for PID match
         If hInstance = ProcIDFromWnd(tempHwnd) Then
            ' Return found handle
            GetWinHandle = tempHwnd
            ' Exit search loop
            Exit Do
         End If
      End If
   
      ' Get the next window handle
      tempHwnd = GetWindow(tempHwnd, GW_HWNDNEXT)
   Loop
End Function

Private Function ProcIDFromWnd(ByVal hWnd As Long) As Long
   Dim idProc As Long
   
   ' Get PID for this HWnd
   GetWindowThreadProcessId hWnd, idProc
   
   ' Return PID
   ProcIDFromWnd = idProc
End Function

I hope that helps you!

[Sathyaish]

Guys, I think I got the real problem. For a test, I made another project with an MDI and two child forms and a call from each of them to GetWindowThreadProcessID revealed that they all shared the same thread ID and but obviously the same process ID too. Now, while looping through all open windows in GethWndFromProcessID, it occured to me that while the ProcessID being matched therein was correct but it could be that one of the child windows was being encountered and its handle being returned to me, which I tried resizing and it had to fail since the MDI within which the child was contained was still minimized. While when I posted a WM_QUIT to the same window handle, it got destroyed. All this led me to think that my theory is somewhat correct. I am acting on a child window handle and so a WM_SIZE fails because the parent is minimized but a WM_QUIT on the child works fine because it passes it on to the MDI parent form.

Now, I think I must use the GetAncestor and return from GethWndFromProcessID only if I encounter the parent/top level MDI form window and not otherwise.

I did a search on my system but could not find Winuser.h. Can one of you please send me the value of GA_ROOT?

[Ungi]

Const GA_ROOT = 2

[Sathyaish]

Thanks, Ungi.