launch batch file

[adam786]

how would i launch a batch file from within visual basic?
the batch file is called kill.bat i have used the following code

 shell "/kill.bat"

but does not work. the bat file is stored in the root where the application would be launched from.

[gavio]

Dim x As String

x = App.Path 

If Right$(x, 1) <> "\" Then x = x & "\"

x = x & "kill.bat"

Shell x, vbNormalFocus

Not tested - from the top of my head

[TheBigB]

Dim x As String

x = App.Path 

If Right$(x, 1) <> "\" Then x = x & "\"

x = x & "kill.bat"

Shell x, vbNormalFocus

Not tested - from the top of my head

Wouldn't the following work fine?

Shell App.Path & "\kill.bat"

I don't disagree with your method, because it should work fine, but is all the code around necessary?
I mean I've never used it that way

[gavio]

@TheBigB: what if EXE is in drive root? "c:\"? Then you have:

Shell "c:\\kill.bat"

... which of course, fails. You must think ahead

My code is still not good enough. He should also check if "kill.bat" actually exists

[TheBigB]

@TheBigB: what if EXE is in drive root? "c:\"? Then you have:

Shell "c:\\kill.bat"

... which of course, fails. You must think ahead

My code is still not good enough. He should also check if "kill.bat" actually exists

Never thought of that
Thanks for pointing that out.

[RobDog888]

@TheBigB: what if EXE is in drive root? "c:\"? Then you have:

Shell "c:\\kill.bat"

... which of course, fails. You must think ahead

My code is still not good enough. He should also check if "kill.bat" actually exists

an alternative to that problem would be to use ShellExecute and specify a working directory of the App.Path it wont matter the root path or not (note the double backslash just as a working example).

Option Explicit

Private Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" ( _
                    ByVal hwnd As Long, _
                    ByVal lpOperation As String, _
                    ByVal lpFile As String, _
                    ByVal lpParameters As String, _
                    ByVal lpDirectory As String, _
                    ByVal nShowCmd As Long) As Long

Private Const SW_HIDE As Long = 0
Private Const SW_SHOWNORMAL As Long = 1
Private Const SW_SHOWMAXIMIZED As Long = 3
Private Const SW_SHOWMINIMIZED As Long = 2

Private Sub Command1_Click()
    ShellExecute Me.hwnd, "open", "\deleteme.txt", vbNullString, "C:\", SW_SHOWNORMAL
End Sub

[lone_REBEL]

I would rather recommend this code. Its much more simple and will do all that is required. And without APIs too.

Dim path As String
path = App.Path
If Right(path,1) <> "\" Then path = path & "\"
path = path & "kill.bat"
If LCase(Dir(path)) <> "kill.bat" Then
   'file does not exist
   MsgBox "The required file does not exist"
Else
   'file exists
   Shell path
End If

[RobDog888]

No need to shy away from APIs as they are on your system from the OS anyways. Its just up to you to decide to call it or not and yes your code is good too. .

This API is just as good too as it adds the backslash if needed.
PathAddBackslash

[lone_REBEL]

You flatter me saying my code is good, LOL.
I don't shy from APIs, its just that they always tend to loosen the programmer's grip over the way things work. They also add the factor of uncertainty to the program and the chances of getting a program crash rise (well for me at least, maybe others don't agree with me). Thats why I always try to do without them.

[RobDog888]

There is less chance of them failing but if they did it would be because of ones coded usage of them but with the non-api approach you are taking more chances and uncertanity as your code didnt go through the rigors of unit testing that MS put the APIs through.

[Merri]

I'm not bringing in anything really new with the following code, just bringing some stuff to think about:

Dim strPath As String

' use string and byte version of Right
If RightB$(App.Path, 2) <> "\" Then
    strPath = App.Path & "\kill.bat"
Else
    strPath = App.Path & "kill.bat"
End If

' another point: because we are finding out where a file (or folder) exists
' and Dir returns a null string if it was not found, we only need to check
' length of the returned string
If LenB(Dir$(strPath)) Then
    Shell strPath
Else
    MsgBox "The file """ & strPath & """ was not found!"
End If

As for ShellExecute, you don't need to do checking beforehand, you can just go ahead and make the function call. However instead you can get an error message out of it as a return value: http://msdn.microsoft.com/en-us/library/bb762153.aspx - although it is of the weirder ones, the return value is an error if it is from 0 to 32, otherwise the return value means success. That is even weirder than most other API functions, where 0 can mean success and any other value is an error; but there are also API functions where 0 means error and you have to use GetLastError API to get the error number, because any other value is a wanted result. But there are also APIs where -1 (or &HFFFFFFFF) is the failing condition. And then we have these functions like ShellExecute that are truly unique with their return values...

[RobDog888]

My full example I usually post but I usually I try to keep it simple

Option Explicit

Private Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, _
ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long

Private Const SW_SHOWNORMAL As Long = 1
Private Const SW_SHOWMINIMIZED As Long = 2
Private Const SW_SHOWMAXIMIZED As Long = 3

Private Const ERROR_FILE_NOT_FOUND As Long = 2&
Private Const ERROR_PATH_NOT_FOUND As Long = 3&
Private Const ERROR_BAD_FORMAT As Long = 11&
Private Const SE_ERR_ACCESSDENIED As Long = 5
Private Const SE_ERR_ASSOCINCOMPLETE As Long = 27
Private Const SE_ERR_DDEBUSY As Long = 30
Private Const SE_ERR_DDEFAIL As Long = 29
Private Const SE_ERR_DDETIMEOUT As Long = 28
Private Const SE_ERR_DLLNOTFOUND As Long = 32
Private Const SE_ERR_FNF As Long = 2
Private Const SE_ERR_NOASSOC As Long = 31
Private Const SE_ERR_OOM As Long = 8
Private Const SE_ERR_PNF As Long = 3
Private Const SE_ERR_SHARE As Long = 26

Private Sub Command1_Click()
    On Error GoTo MyError
    Dim lRet As Long
    lRet = ShellExecute(Me.hwnd, "Open", "CMD.exe", " /C ipconfig.exe /all > C:\ip.txt", "C:\", SW_SHOWNORMAL)
    If lRet <= 32 Then
        Select Case lRet
            Case 0
                MsgBox "The operating system is out of memory or resources."
            Case ERROR_FILE_NOT_FOUND
                MsgBox "The specified file was not found."
            Case ERROR_PATH_NOT_FOUND
                MsgBox "The specified path was not found."
            Case ERROR_BAD_FORMAT
                MsgBox "The .EXE file is invalid (non-Win32 .EXE or error in .EXE image)."
            Case SE_ERR_ACCESSDENIED
                MsgBox "The operating system denied access to the specified file."
            Case SE_ERR_ASSOCINCOMPLETE
                MsgBox "The filename association is incomplete or invalid."
            Case SE_ERR_DDEBUSY
                MsgBox "The DDE transaction could not be completed because other DDE transactions were being processed."
            Case SE_ERR_DDEFAIL
                MsgBox "The DDE transaction failed."
            Case SE_ERR_DDETIMEOUT
                MsgBox "The DDE transaction could not be completed because the request timed out."
            Case SE_ERR_DLLNOTFOUND
                MsgBox "The specified dynamic-link library was not found."
            Case SE_ERR_FNF
                MsgBox "The specified file was not found."
            Case SE_ERR_NOASSOC
                MsgBox "There is no application associated with the given filename extension."
            Case SE_ERR_OOM
                MsgBox "There was not enough memory to complete the operation."
            Case SE_ERR_PNF
                MsgBox "The specified path was not found."
            Case SE_ERR_SHARE
                MsgBox "A sharing violation occurred."
        End Select
    End If
    Exit Sub
MyError:
    MsgBox Err.Number & " - " & Err.Description
End Sub

[TheBigB]

Nice
That's some fool-proof code over there

You flatter me saying my code is good, LOL.
I don't shy from APIs, its just that they always tend to loosen the programmer's grip over the way things work. They also add the factor of uncertainty to the program and the chances of getting a program crash rise (well for me at least, maybe others don't agree with me). Thats why I always try to do without them.

You're right in a way, but you have to face that ShellExecute provides more functionality than Shell. In addition, API calls speed up your code, because it's a direct link from the code, rather than a redirection from the VB runtime.

[anhn]

Perhaps ShellExecute is better way nowadays as some systems may block Shell command.

This is a revived version of lone_REBEL's code in post#7, it also looks similar to Merri's code in post#11.

Sub KillIt()
   Dim sPath As String
   
   sPath = Replace(App.Path & "\kill.bat", "\\", "\") '-- cheating an If (I am lazy)  
   If Len(Dir(sPath)) Then '-- the file exists
      Shell sPath
   Else
      MsgBox "File Not Found: " & sPath
   End If
End Sub

[TheBigB]

Perhaps ShellExecute is better way nowadays as some systems may block Shell command.

This is a revived version of lone_REBEL's code in post#7, it also looks similar to Merri's code in post#11.

Sub KillIt()
   Dim sPath As String
   
   sPath = Replace(App.Path & "\kill.bat", "\\", "\") '-- cheating an If (I am lazy)  
   If Len(Dir(sPath)) Then '-- the file exists
      Shell sPath
   Else
      MsgBox "File Not Found: " & sPath
   End If
End Sub

What if the application is ran on a network location
\\server\

[anhn]

What if the application is ran on a network location
\\server\

You know how to fix it.

[Merri]

You don't really need to clean up the \ character though:

Option Explicit

Private Sub Form_Load()
    Dim strPath As String
    strPath = "C:\Windows\\Win.ini"
    If LenB(Dir$(strPath)) Then Debug.Print "File exists"
End Sub

You can even put \\\\\\\\\\\\\\\\\\\\\ in and it still says the file exists...

Option Explicit

Private Declare Function ShellExecuteW Lib "shell32.dll" (ByVal hWnd As Long, ByVal lpOperation As Long, ByVal lpFile As Long, ByVal lpParameters As Long, ByVal lpDirectory As Long, ByVal nShowCmd As Long) As Long

Private Sub Form_Load()
    Dim strPath As String
    strPath = "C:\\\\\\\\\\\\\\\\\\Windows\\\\\\\\\\\\\\\\Win.ini"
    If LenB(Dir$(strPath)) Then
        If ShellExecuteW(Me.hWnd, StrPtr("Open"), StrPtr(strPath), 0, 0, 1) > 32 Then
            Debug.Print "Success!"
        End If
    End If
End Sub

Success! (Also showing how to make Unicode call since all the others prefer ANSI... using Dir$ spoils this one though)

[anhn]

You don't really need to clean up the \ character though

Good info, Merri. That's modern technology!

The bat file may exist but if it cannot be run then the Shell() function will return 0. How about this:

Sub RunBatFile(sBatFileName As String, Optional ByVal sPath As String)
   Dim ID As Double
   
   If sPath = "" Then sPath = App.Path
   On Error Resume Next
   ID = Shell(sPath & "\" & sBatFileName)
   If ID = 0 Then MsgBox "Cannot run bat file: " & sBatFileName
End Sub

(Don't hate "On Error Resume Next". It's a good statement if we use it properly.)