Having Trouble Killing App that aks

**Lawson** · Dec 5th, 2000, 04:42 PM

Hello all.

I am trying to use VB code to close another program which is already running. I can di that using the code below labeled CODE EXAMPLE ONE. However, this does not do the job when the application which I am trying to close pops up a message box window prompting user for input "Are you sure"...

I found some code posted by Matthew Gates & it looks like what I need. However (there's that word again!), I get a runtime error 453 - can't find dll entry point when the CreateToolhelpSnapshot function is called in the code below labeled CODE EXAMPLE TWO.

Do I need a different version of kernel32.dll?
I am using VB6, NT4.0, sp6.

Any help will be greatly appreciated.

Code:

'CODE EXAMPLE ONE:  ***************************************

'Module code
Option Explicit



Public Const WM_DESTROY = &H2
Public Const WM_CLOSE = &H10

Public RETURN_HANDLE As Long

Public Const TH32CS_SNAPPROCESS As Long = 2&
Public Const MAX_PATH As Long = 260

Public sAppTitle As String
Public glHwnd As Long

Public Type PROCESSENTRY32
    dwSize As Long
    cntUsage As Long
    th32ProcessID As Long
    th32DefaultHeapID As Long
    th32ModuleID As Long
    cntThreads As Long
    th32ParentProcessID As Long
    pcPriClassBase As Long
    dwflags As Long
    szexeFile As String * MAX_PATH
End Type

Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
    (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Declare Function PostMessage Lib "user32" Alias "PostMessageA" _
    (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _
    ByVal lParam As Long) As Long
Declare Function EnumWindows Lib "user32" _
    (ByVal lpEnumFunc As Long, ByVal lParam As Long) As Long
Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" _
    (ByVal hWnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
Public Declare Function GetWindowThreadProcessId Lib "user32" (ByVal hWnd As Long, lpdwProcessId As Long) As Long
Public Declare Function CreateToolhelpSnapshot Lib "c:\winnt\system32\Kernel32.dll" Alias "CreateToolhelp32Snapshot" (ByVal lFlgas As Long, ByVal lProcessID As Long) As Long
Public Declare Function ProcessFirst Lib "Kernel32" Alias "Process32First" (ByVal hSnapshot As Long, uProcess As PROCESSENTRY32) As Long
Public Declare Function ProcessNext Lib "Kernel32" Alias "Process32Next" (ByVal hSnapshot As Long, uProcess As PROCESSENTRY32) As Long
Public Declare Sub CloseHandle Lib "Kernel32" (ByVal hPass As Long)

Public Function GetExeFromHandle(hWnd As Long) As String
    Dim threadID As Long, processID As Long, hSnapshot As Long
    Dim uProcess As PROCESSENTRY32, rProcessFound As Long
    Dim i As Integer, szExename As String
    ' Get ID for window thread
    
  
    threadID = GetWindowThreadProcessId(hWnd, processID)
    ' Check if valid
    If threadID = 0 Or processID = 0 Then Exit Function
    ' Create snapshot of current processes
    hSnapshot = CreateToolhelpSnapshot(TH32CS_SNAPPROCESS, 0&)
    ' Check if snapshot is valid
    If hSnapshot = -1 Then Exit Function
    'Initialize uProcess with correct size
    uProcess.dwSize = Len(uProcess)
    'Start looping through processes
    rProcessFound = ProcessFirst(hSnapshot, uProcess)
    Do While rProcessFound
        If uProcess.th32ProcessID = processID Then
            'Found it, now get name of exefile
            i = InStr(1, uProcess.szexeFile, Chr(0))
        
            If i > 0 Then szExename = Left$(uProcess.szexeFile, i - 1)
            Exit Do
        Else
            'Wrong ID, so continue looping
            rProcessFound = ProcessNext(hSnapshot, uProcess)
        End If
        
    Loop
    Call CloseHandle(hSnapshot)
    GetExeFromHandle = szExename
End Function




Public Function fEnumWindowsCallBack(ByVal hWnd As Long, ByVal lpData As Long) As Long
    Dim lResult    As Long
    Dim sWndName   As String
     
    fEnumWindowsCallBack = 1
    sWndName = Space$(MAX_PATH)
     
    lResult = GetWindowText(hWnd, sWndName, MAX_PATH)
    sWndName = Left$(sWndName, lResult)
    'Search Title for our string
    If (InStr(1, sWndName, sAppTitle, vbTextCompare) > 0) Then
        Debug.Print sWndName
        glHwnd = hWnd
        fEnumWindowsCallBack = 0
    End If
End Function

Public Function SearchWindows(sApp As String, hWnd As Long) As Long
    sAppTitle = sApp
    glHwnd = 0
    Call EnumWindows(AddressOf fEnumWindowsCallBack, hWnd)
    SearchWindows = glHwnd
End Function

'Form code
Private Sub Command2_Click()
  Dim sApp As String
    'Find notepad - or name of any exe- with partial name
    sApp = "note"
    glHwnd = SearchWindows(sApp, Me.hWnd)
   
    If glHwnd > 0 Then
        PostMessage glHwnd, WM_CLOSE, 0&, 0&
    End If
End Sub
'****************end code example one***********************

'CODE EXAMPLE TWO: ************

'NOTE - this code uses the same module declarations 
'functions as the above code.

Private Sub Command2_Click()
  Dim sApp As String
    'Find app with partial name
    sApp = "sampleAppName"
    
    glHwnd = SearchWindows(sApp, Me.hWnd)
    
    If glHwnd > 0 Then
         RETURN_HANDLE = glHwnd
         Label1.Caption = RETURN_HANDLE
    End If

End Sub

Private Sub Command4_Click()
Dim exeNameStr As String

exeNameStr = GetExeFromHandle(RETURN_HANDLE)
End Sub

[Edited by Lawson on 12-06-2000 at 11:51 AM]

Dec 5th, 2000, 10:34 PM

Isn't NT 16 bit?
Try changing:
user32, Kernel32
To:
user, Kernel

**dsy5** · Dec 5th, 2000, 11:12 PM

NT 4.0 is 32 bit. I made an app once which would kill an application that had the focus.
I too had trouble with the "Are you sure" type message box. I don't remember offhand how
I got rid of the messagebox - I'll see if I can dig up the project.

**Lawson** · Dec 6th, 2000, 11:37 AM

Thanks for the info!

I figured out how to shut down the application with the "Are you sure" message box. I'll post the code below. However (...that word again...), I'd still like to figure out why I am unable to access the kernel32 functions. The kernel32.dll & user32.dll exist in c:\winnt\system32 - one of the first things I checked.

Anyway, here is the code that works for me.

Code:

'MODULE PAGE:
Option Explicit

Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
    (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Declare Function PostMessage Lib "user32" Alias "PostMessageA" _
    (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _
    ByVal lParam As Long) As Long
Declare Function EnumWindows Lib "user32" _
    (ByVal lpEnumFunc As Long, ByVal lParam As Long) As Long
Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" _
    (ByVal hWnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
 Declare Function GetWindowThreadProcessId Lib "user32" (ByVal hWnd As Long, lpdwProcessId As Long) As Long
 Declare Function CreateToolhelpSnapshot Lib "c:\winnt\system32\Kernel32.dll" Alias "CreateToolhelp32Snapshot" (ByVal lFlgas As Long, ByVal lProcessID As Long) As Long
 Declare Function ProcessFirst Lib "Kernel32" Alias "Process32First" (ByVal hSnapshot As Long, uProcess As PROCESSENTRY32) As Long
 Declare Function ProcessNext Lib "Kernel32" Alias "Process32Next" (ByVal hSnapshot As Long, uProcess As PROCESSENTRY32) As Long
 Declare Sub CloseHandle Lib "Kernel32" (ByVal hPass As Long)


Public Const WM_DESTROY = &H2
Public Const WM_CLOSE = &H10

Public RETURN_HANDLE As Long

Public Const TH32CS_SNAPPROCESS As Long = 2&
Public Const MAX_PATH As Long = 260

Public sAppTitle As String
Public glHwnd As Long

Public Type PROCESSENTRY32
    dwSize As Long
    cntUsage As Long
    th32ProcessID As Long
    th32DefaultHeapID As Long
    th32ModuleID As Long
    cntThreads As Long
    th32ParentProcessID As Long
    pcPriClassBase As Long
    dwflags As Long
    szexeFile As String * MAX_PATH
End Type


Public Function GetExeFromHandle(hWnd As Long) As String
    Dim threadID As Long, processID As Long, hSnapshot As Long
    Dim uProcess As PROCESSENTRY32, rProcessFound As Long
    Dim i As Integer, szExename As String
    ' Get ID for window thread
    
  
    threadID = GetWindowThreadProcessId(hWnd, processID)
    ' Check if valid
    If threadID = 0 Or processID = 0 Then Exit Function
    ' Create snapshot of current processes
    hSnapshot = CreateToolhelpSnapshot(TH32CS_SNAPPROCESS, 0&)
    ' Check if snapshot is valid
    If hSnapshot = -1 Then Exit Function
    'Initialize uProcess with correct size
    uProcess.dwSize = Len(uProcess)
    'Start looping through processes
    rProcessFound = ProcessFirst(hSnapshot, uProcess)
    Do While rProcessFound
        If uProcess.th32ProcessID = processID Then
            'Found it, now get name of exefile
            i = InStr(1, uProcess.szexeFile, Chr(0))
        
            If i > 0 Then szExename = Left$(uProcess.szexeFile, i - 1)
            Exit Do
        Else
            'Wrong ID, so continue looping
            rProcessFound = ProcessNext(hSnapshot, uProcess)
        End If
        
    Loop
    Call CloseHandle(hSnapshot)
    GetExeFromHandle = szExename
End Function




Public Function fEnumWindowsCallBack(ByVal hWnd As Long, ByVal lpData As Long) As Long
    Dim lResult    As Long
    Dim sWndName   As String
     
    fEnumWindowsCallBack = 1
    sWndName = Space$(MAX_PATH)
     
    lResult = GetWindowText(hWnd, sWndName, MAX_PATH)
    sWndName = Left$(sWndName, lResult)
    'Search Title for our string
    If (InStr(1, sWndName, sAppTitle, vbTextCompare) > 0) Then
        Debug.Print sWndName
        glHwnd = hWnd
        fEnumWindowsCallBack = 0
    End If
End Function

Public Function SearchWindows(sApp As String, hWnd As Long) As Long
    sAppTitle = sApp
    glHwnd = 0
    Call EnumWindows(AddressOf fEnumWindowsCallBack, hWnd)
    SearchWindows = glHwnd
End Function

 

'FORM:

Private Sub Command5_Click()
 Dim sApp As String
    
    'Find application running with partial name
     sApp = "System Control"
    
    glHwnd = SearchWindows(sApp, Me.hWnd)
    

    If glHwnd > 0 Then
    
         RETURN_HANDLE = glHwnd
         Label1.Caption = RETURN_HANDLE
        PostMessage glHwnd, WM_CLOSE, 0&, 0&
        PostMessage glHwnd, WM_DESTROY, 0&, 0&
        PostMessage glHwnd, WM_DESTROY, 0&, 0&
        PostMessage glHwnd, WM_DESTROY, 0&, 0&
        'this may work with only one "destroy", it 
        'works this way - so I left it for now
    End If
  
End Sub

[Edited by Lawson on 12-06-2000 at 11:49 AM]

Thread: Having Trouble Killing App that aks

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