asked on

Waiting until a part of the process ended

Hello,

I've got a little problem with my program. I use the shell-command and until my shell-command isn't ended my program has to wait with executing the rest of the subprocedure. Can someone provide me with some easy code.

Can someone also tell me what value I get if my shell-command ends?

Thanx

ASKER CERTIFIED SOLUTION

Jonyv

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Éric Moreau

Use this:

Option Explicit

Private Declare Function WaitForSingleObject _
Lib "kernel32" _
(ByVal hHandle As Long, _
ByVal dwMilliseconds 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 Const INFINITE = &HFFFF

Private Sub Command1_Click()
WaitForProcessToEnd "CALC.EXE"
End Sub

Private Function WaitForProcessToEnd(ByVal pstrExecute As String) As Boolean
'**********************************************************************
'*** Execute a process an wait for it to end before continuing here ***
'**********************************************************************
Dim lngHandle As Long
Dim lngProcessID As Long
Dim lngReturnValue As Long

On Error GoTo ErrorHandler

WaitForProcessToEnd = False

lngProcessID = Shell(pstrExecute)
lngHandle = OpenProcess(&H100000, True, lngProcessID)
lngReturnValue = WaitForSingleObject(lngHandle, INFINITE)

MsgBox "Here is the proof that I was waiting!!!"

WaitForProcessToEnd = True

GoHere:
Exit Function

ErrorHandler:
Select Case Err.Number
Case 53 'File not found
MsgBox pstrExecute & " cannot be found.", vbOKOnly + vbCritical
Resume GoHere
Case Else
MsgBox Err.Number & " : " & Err.Description
Resume GoHere
End Select
End Function

Jonyv

Well, WaitForSingleObject works fine too, but the drawback is that the VB application may look as if it's hanged since it's windows aren't repainted during the wait, that's why I personally prefer the polling method used in my example. But you may of course use whatever method you like.

Pingolin

ASKER

Thanx, that was just wat i wanted. Now my program is completed!