ShellExecuteEx help!

[hgroot]

Hi,

I have this 'slight' problem using ShellExecuteEx (after having tried all alternatives: CreateProcess, Shell(), ShellExecute)

When I feed it with a filename for which an association exists, it's no problem. (.txt - Notepad starts and runs...)

But when I feed it with an executable, I can barely see the outline of the window (so it has been started!), before Windows mysteriously decides to immediately close it. I end up with a pid of a non-existent process...

Can someone please help? Would it be part of NT4 workstation restrictions?

Here's the code:

Public Declare Function ShellExecuteEx Lib "shell32.dll" (ShellExecuteInfo As ShellExecuteInfoType) As Long

Public Const SEE_MASK_INVOKEIDLIST = &HC
Public Const SEE_MASK_NOCLOSEPROCESS = &H40
Public Const SEE_MASK_FLAG_NO_UI = &H400

Private Type ShellExecuteInfoType
    cbSize As Long
    fMask As Long
    hwnd As Long
    lpVerb As String
    lpFile As String
    lpParameters As String
    lpDirectory As String
    nShow As Long
    hInstApp As Long
    lpIDList As Long
    lpClass As String
    hkeyClass As Long
    dwHotKey As Long
    hIcon As Long
    hProcess As Long
End Type

Public Function StartApplication(ApplicationName As String) As Long
    Dim theShellExecuteInfo As ShellExecuteInfoType
    Dim ret As Long
    Dim hwnd As Long
    
    With theShellExecuteInfo
        .cbSize = Len(theShellExecuteInfo)
        .fMask = SEE_MASK_NOCLOSEPROCESS Or SEE_MASK_INVOKEIDLIST Or _
            SEE_MASK_FLAG_NO_UI
        
        .hwnd = Me.hWnd
        .lpVerb = "open"
       
        .lpFile = ApplicationName & vbNullChar
        .lpParameters = vbNullChar
        .lpDirectory = vbNullChar
        .nShow = 0
        .hInstApp = 0
        .lpIDList = 0
    End With
    
    ret = ShellExecuteEx(theShellExecuteInfo)
    StartApplication = theShellExecuteInfo.hProcess
End Function

[jim mcnamara]

When that happens, it usually means one of the parameters, the default directory, or some other element you need is missing.

Try running your command from a .BAT file, or from the DOS prompt. You may see the error return. Also check the exit status of the process. If it is not zero, then it ended with an error. You can get the status with GetExitCodeProcess(hProcess).

[hgroot]

Thanks!

I laced the code with debug statements and traced the problem. I also used one 'on error goto' too many..

But even without that - No error codes whatsoever. Now I know I've always underestimated VB programming...

[hgroot]

The problem in the piece of code I posted was that it did open a process, but didn't show it (missing .nShow constant!)

But I have this new problem:
ShellExecuteEx returns a process handle and I need the process identifier. I've searched for some API call to get the ID for a specific handle, but I can only find routines that do the oposite - convert ID into handle...

Do you have any suggestions?

[Vasconcelos]

If you need to get the process identifier, I think there´s only two ways: using the GetCurrentProcessId function (that returns the process identifier of the calling process) or using the CreateProcess function instead of ShellExecuteEx, cause a PROCESS_INFORMATION structure is filled in by this way.