End Process from Task Manager using VB 6 Code

Question

I need to kill an application roughly so I can get phantom subscriber of that application in my database (this can not be produced by closing the application). Manually, if we kill the application from Task Manager, the phantom subscriber will be exist. Now I need to do it automatically in VB 6 code. Help! Thanks.

Answer 1

Hi, There are two ways: 1. Send WM_CLOSE to the target application if it has a window (hidden/visible). Task Manager's "End Task" uses this method. Most of the applications handle WM_CLOSE and terminate gracefully. 2. Use TerminateProcess APi to kill forcefully - Task Manager's "End Process" uses this method. This API forcefully kills the process.

An example can be found here: http://www.vb-helper.com/howto%5Fterminate%5Fprocess.html

Answer 2

Call ShellExecute with the TaskKill command

TASKKILL [/S system [/U username [/P [password]]]] { [/FI filter] [/PID processid | /IM imagename] } [/T] [/F]

Description: This tool is used to terminate tasks by process id (PID) or image name.

Answer 3

    Option Explicit

Private Declare Function IsWindow Lib "user32" (ByVal hWnd As Long) As Long
Private Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Private Declare Function TerminateProcess Lib "kernel32" (ByVal hProcess As Long, ByVal uExitCode As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function GetWindowThreadProcessId Lib "user32" (ByVal hWnd As Long, lpdwProcessId As Long) As Long
Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Public Declare Function EnumWindows Lib "user32" (ByVal lpEnumFunc As Long, ByVal lParam As Long) As Long
Public Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hWnd As Long, ByVal lpString As String, ByVal cch As Long) As Long


Private Const PROCESS_ALL_ACCESS = &H1F0FFF

Private Target As String

'---------------------------------------------------------------------------------------
' Creation Date :   24/10/2005 09:03
' Created By    :   Jason Bruwer
' Purpose         :   Returns the windows handle of a window if you know the name
'                    :   E.g.
'                           Microsoft Word
'                           Microsoft Excel
'                           Microsoft PowerPoint
'                           Adobe Reader
' Updated By    :   [Initials] - [Date] - [Changes]
'---------------------------------------------------------------------------------------
Public Function GetWindowsHandle(WindowName As String, hWindow As Long) As Boolean

    On Error GoTo Errors

    ' Get the target's window handle.
    hWindow = FindWindow(vbNullString, WindowName)

    If hWindow = 0 Then GoTo Cheers

    GetWindowsHandle = True

Cheers:
    Exit Function
Errors:
    frmMain.LogErrorAcrossUsingRBT ("GetWindowsHandle")
    GoTo Cheers
End Function


'---------------------------------------------------------------------------------------
' Creation Date :   24/10/2005 09:03
' Created By    :   Jason Bruwer
' Purpose        :   Enumerates all the currently open windows and searches for an application
'                        with the specified name.
' Updated By    :   [Initials] - [Date] - [Changes]
'---------------------------------------------------------------------------------------
Public Function TerminateTask(app_name As String) As Boolean

On Error GoTo Errors

Target = UCase(app_name)
EnumWindows AddressOf EnumCallback, 0

TerminateTask = True

Cheers:
Exit Function
Errors:
frmMain.LogErrorAcrossUsingRBT ("TerminateTask")
GoTo Cheers
End Function


'---------------------------------------------------------------------------------------
' Creation Date :   24/10/2005 09:04
' Created By    :   Jason Bruwer
' Purpose         :  Checks to see if this is the window we are looking for and then trys
'                        to kill the application
' Updated By    :   [Initials] - [Date] - [Changes]
'---------------------------------------------------------------------------------------
Public Function EnumCallback(ByVal app_hWnd As Long, ByVal param As Long) As Long
Dim buf As String * 256
Dim title As String
Dim length As Long

' Get the window's title.
length = GetWindowText(app_hWnd, buf, Len(buf))
title = Left$(buf, length)

'If title <> "" Then Debug.Print title

' See if this is the target window.
If InStr(UCase(title), Target) <> 0 Then
    ' Kill the window.
    If Not KillProcess(app_hWnd) Then Exit Function
End If

' Continue searching.
EnumCallback = 1

End Function


'---------------------------------------------------------------------------------------
' Creation Date :   24/10/2005 09:06
' Created By    :   Jason Bruwer
' Purpose         :  Trys to kill an application by using its windows handle
' Updated By    :   [Initials] - [Date] - [Changes]
'---------------------------------------------------------------------------------------
Public Function KillProcess(hWindow As Long) As Boolean
Dim RetrunValue As Long
Dim ProcessValue As Long
Dim ProcessValueID As Long
Dim ThreadID As Long

    On Error GoTo Errors

    If (IsWindow(hWindow) <> 0) Then
      ThreadID = GetWindowThreadProcessId(hWindow, ProcessValueID)

      If (ProcessValueID <> 0) Then
        App.LogEvent "Warning...killing orphan process..."

        ProcessValue = OpenProcess(PROCESS_ALL_ACCESS, CLng(0), ProcessValueID)
        RetrunValue = TerminateProcess(ProcessValue, CLng(0))
        CloseHandle ProcessValueID
      End If

    End If

    KillProcess = True

Cheers:
    Exit Function
Errors:
    frmMain.LogErrorAcrossUsingRBT ("KillProcess")
    GoTo Cheers
End Function

Answer 4

Karl Peterson's excellent archive of VB6 code has high quality sample code and full explanations using both WM_CLOSE and TerminateProcess. Accept no substitutes!

One pitfall you might see in a lot of code out there is that sending WM_CLOSE to a single window handle you have isn't sufficient - most applications comprise numerous windows. The answer as implemented in Karl's code: Find all the top-level windows belonging to this application and send the message to each.

Answer 5

Shell "taskkill.exe /f /t /im processname.exe"

This forces (/f) the terminatation of the process with the image name (/im) of processname.exe, and any child processes which were started by it (/t). You may not need all these switches. See the taskkill command help for more information (type the following at the command line):

taskkill/?