When launching an .exe using .Run in VBA, a typical call may look like this:
x = wsh.Run(Command:="program.exe ""argument""", WindowStyle:=0, waitonreturn:=False)
Where windowStyle=0 should theoretically cause the program to run invisible to the user. But what if a pop-up window occurs within the .exe that you don't want to the user to see?
The windowStyle input will not suppress the appearance of warning messages or pop up windows declaring things like 'calculation complete' from appearing to the user, this often also pauses the code until the pop up is cleared. Clearing the window (i.e. clicking 'okay') in an automated manner is trivial (see this answer), but preventing it from appearing to the user to begin with is proving difficult to me as a relative beginner. (i.e. when the pop up is triggered by the .exe it is invisible to the user, and then closed automatically by the VBA code)
Currently I detect the existence of a new pop up window using this function (where sCaption is the name of the pop up window):
Private Function GetHandleFromPartialCaption(ByRef lWnd As Long, ByVal sCaption As String) As Boolean
Dim lhWndP As Long
Dim sStr As String
GetHandleFromPartialCaption = False
lhWndP = FindWindow(vbNullString, vbNullString) 'PARENT WINDOW
Do While lhWndP <> 0
sStr = String(GetWindowTextLength(lhWndP) + 1, Chr$(0))
GetWindowText lhWndP, sStr, Len(sStr)
sStr = Left$(sStr, Len(sStr) - 1)
If InStr(1, sStr, sCaption) > 0 Then
GetHandleFromPartialCaption = True
lWnd = lhWndP
Exit Do
End If
lhWndP = GetWindow(lhWndP, GW_HWNDNEXT)
Loop
End Function
Then close it automatically. But it still briefly flashes up on screen to the user. Ideally I'd like this VBA code to run in the background so the user can get on with other tasks whilst it runs, not being distracted by flashing boxes.
Is there a way to force all windows of program.exe, including pop ups, to be invisible whilst it is running?
For further information, see my previous question on how to close the pop up window, here. This thread concerns how to prevent its appearance to a user.
EDIT 1
SendKeys is temperamental, so I am using this looping code to kill the .exe when I detect the pop up window, therefore the .exe does not need to be in focus to close the pop up (closing the pop up kills the .exe in my case anyway):
....
Main Code Body
....
t = Now
waittime = Now + TimeValue("0:01:30") 'limit to run a single row of calculations
Do While t < waittime
If GetHandleFromPartialCaption(lhWndP, "Popup Window Text") = True Then
Set oServ = GetObject("winmgmts:")
Set cProc = oServ.ExecQuery("Select * from Win32_Process")
For Each oProc In cProc
If oProc.Name = "Program.exe" Then
errReturnCode = oProc.Terminate()
Marker2 = 1
Exit Do
End If
Next
Endif
Loop
....
Main Code Body Continues
....
where GetHandleFromPartialCaption() is the function above, finding the pop up window based on the sCaption argument. My code loops and searches constantly for the pop up whilst the .exe is running the calculation, and kills the .exe as soon as it appears. But it still flashes up to the user.
To run an application completely hidden, launch it in a different desktop with CreateProcess.
Here's an example executing a simple command line and waiting for the process to exit :
Option Explicit
Private Declare PtrSafe Function OpenDesktop Lib "user32.dll" Alias "OpenDesktopW" (ByVal lpszDesktop As LongPtr, ByVal dwFlags As Long, ByVal fInherit As Byte, ByVal dwDesiredAccess As Long) As LongPtr
Private Declare PtrSafe Function CreateDesktop Lib "user32.dll" Alias "CreateDesktopW" (ByVal lpszDesktop As LongPtr, ByVal lpszDevice As LongPtr, ByVal pDevmode As LongPtr, ByVal dwFlags As Long, ByVal dwDesiredAccess As Long, ByVal lpsa As LongPtr) As LongPtr
Private Declare PtrSafe Function CloseDesktop Lib "user32.dll" (ByVal hDesktop As LongPtr) As Long
Private Declare PtrSafe Function CreateProcess Lib "kernel32.dll" Alias "CreateProcessW" (ByVal lpApplicationName As LongPtr, ByVal lpCommandLine As LongPtr, ByVal lpProcessAttributes As LongPtr, ByVal lpThreadAttributes As LongPtr, ByVal bInheritHandles As Byte, ByVal dwCreationFlags As Long, ByVal lpEnvironment As LongPtr, ByVal lpCurrentDirectory As LongPtr, ByRef lpStartupInfo As STARTUPINFO, ByRef lpProcessInformation As PROCESS_INFORMATION) As Long
Private Declare PtrSafe Function WaitForSingleObject Lib "kernel32.dll" (ByVal hHandle As LongPtr, ByVal dwMilliseconds As Long) As Long
Private Declare PtrSafe Function GetExitCodeProcess Lib "kernel32.dll" (ByVal hProcess As LongPtr, ByRef lpExitCode As Long) As Long
Private Declare PtrSafe Function CloseHandle Lib "kernel32.dll" (ByVal hObject As LongPtr) As Long
Private Declare PtrSafe Function GetWindowText Lib "user32.dll" Alias "GetWindowTextW" (ByVal hwnd As LongPtr, ByVal lpString As LongPtr, ByVal nMaxCount As Long) As Long
Private Declare PtrSafe Function EnumDesktopWindows Lib "user32.dll" (ByVal hDesktop As LongPtr, ByVal lpfn As LongPtr, ByRef lParam As Any) As Long
Private Declare PtrSafe Function SendMessageW Lib "user32.dll" (ByVal hwnd As LongPtr, ByVal wMsg As Long, ByVal wParam As LongPtr, ByVal lParam As LongPtr) As LongPtr
Private Declare PtrSafe Function GetLastError Lib "kernel32.dll" () As Long
Private Type STARTUPINFO
cb As Long
lpReserved As LongPtr
lpDesktop As LongPtr
lpTitle As LongPtr
dwX As Long
dwY As Long
dwXSize As Long
dwYSize As Long
dwXCountChars As Long
dwYCountChars As Long
dwFillAttribute As Long
dwFlags As Long
wShowWindow As Integer
cbReserved2 As Integer
lpReserved2 As LongPtr
hStdInput As LongPtr
hStdOutput As LongPtr
hStdError As LongPtr
End Type
Private Type PROCESS_INFORMATION
hProcess As LongPtr
hThread As LongPtr
dwProcessID As Long
dwThreadID As Long
End Type
Public Sub UsageExample()
Dim exitCode As Long
exitCode = ExecuteHidden("cmd /C echo abcd > %USERPROFILE%\Desktop\output.txt", timeoutMs:=10000)
End Sub
Public Function ExecuteHidden(command As String, timeoutMs As Long) As Long
Dim si As STARTUPINFO, pi As PROCESS_INFORMATION, hDesktop As LongPtr, ex As Long
Const NORMAL_PRIORITY_CLASS& = &H20&, INFINITE& = &HFFFFFFFF, GENERIC_ALL& = &H10000000
On Error GoTo Catch
' get a virtual desktop '
si.lpDesktop = StrPtr("hidden-desktop")
hDesktop = OpenDesktop(si.lpDesktop, 0, 0, GENERIC_ALL)
If hDesktop Then Else hDesktop = CreateDesktop(si.lpDesktop, 0, 0, 0, GENERIC_ALL, 0)
If hDesktop Then Else Err.Raise GetLastError()
' run the command '
si.cb = LenB(si)
If CreateProcess(0, StrPtr(command), 0, 0, 1, NORMAL_PRIORITY_CLASS, 0, 0, si, pi) Then Else Err.Raise GetLastError()
' wait for exit '
If WaitForSingleObject(pi.hProcess, timeoutMs) Then Err.Raise 1000, , "Timeout while waiting for the process to exit"
If GetExitCodeProcess(pi.hProcess, ExecuteHidden) <> 0 Then Else Err.Raise GetLastError()
' cleanup '
Catch:
If pi.hThread Then CloseHandle pi.hThread
If pi.hProcess Then CloseHandle pi.hProcess
If hDesktop Then CloseDesktop hDesktop
If Err.Number Then Err.Raise Err.Number
End Function
And if you need to find a window in the desktop, use EnumDesktopWindows instead of EnumWindows:
Private Function FindWindow(ByVal hDesktop As LongPtr, title As String) As LongPtr
Dim hwnds As New Collection, hwnd, buffer$
buffer = Space$(1024)
EnumDesktopWindows hDesktop, AddressOf EnumDesktopWindowsProc, hwnds
For Each hwnd In hwnds
If Left$(buffer, GetWindowText(hwnd, StrPtr(buffer), Len(buffer))) Like title Then
FindWindow = hwnd
Exit Function
End If
Next
End Function
Private Function EnumDesktopWindowsProc(ByVal hwnd As LongPtr, hwnds As Collection) As Long
hwnds.Add hwnd
EnumDesktopWindowsProc = True
End Function
If you need to close a window, simply send WM_CLOSE to the main window or to a popup:
const WM_CLOSE& = &H10&
SendMessageW hwnd, WM_CLOSE, 0, 0