How to block/delay event?

[sonnyzhang]

In VB6, is there a way to block or delay an event ? I want to finish my transaction process before the program go to other event handler.

[Confucius]

Sonnyzhang,

This might help. Not sure if it's exactly what you're looking for.

'Declaration of Synchronizing Windows applications
Public Const PROCESS_ALL_ACCESS = 2035711  '(&H1F0FFF)
Public Const INFINITE = -1                 '(&HFFFFFFFF)
Public Const WAIT_FAILED = -1              '(&HFFFFFFFF)
Public Const STILL_ACTIVE = 259            '(&H103)
Public Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Public Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long
Public Declare Function GetExitCodeProcess Lib "kernel32" (ByVal hProcess As Long, lpExitCode As Long) As Long



Public Function WaitOnProgram(ByVal idProg As Long, Optional ByVal WaitDead As Boolean) As Long
    
    Dim cRead As Long, iExit As Long, hProg As Long
    
    ' Get process handle
    hProg = OpenProcess(PROCESS_ALL_ACCESS, False, idProg)
    If WaitDead Then
        ' Stop dead until process terminates
        Dim iResult As Long
        iResult = WaitForSingleObject(hProg, INFINITE)
        If iResult = WAIT_FAILED Then 'ErrRaise Err.LastDllError
            MsgBox "Error during Shell command"
        End If
        ' Get the return value
        GetExitCodeProcess hProg, iExit
    Else
        ' Get the return value
        GetExitCodeProcess hProg, iExit
        ' Wait, but allow painting and other processing
        Do While iExit = STILL_ACTIVE
            DoEvents
            GetExitCodeProcess hProg, iExit
        Loop
    End If
'    CloseHandle hProg
    WaitOnProgram = iExit
    
End Function

Public Sub RunSyncro(appname As String)

    Dim idProg As Double
    Dim iExit As Long
    Dim temp As String
     
    temp = appname ' & commandLine
    idProg = Shell(temp, 1)
    iExit = WaitOnProgram(idProg)
    If iExit <> 0 Then
        MsgBox App.Title & " could not find " & """" & appname & """", 48
    End If

End Sub


' How to use

  cmdCreateFile.Enabled = False
  RunSyncro ("Notepad.exe C:\Test\TestFile.txt")
  cmdCreateFile.Enabled = True

In this example the cmdCreateFile.Enabled will not be reset until you are done with Notepad.

[sonnyzhang]

Hi Confucius,

Your code gives me some hints. But it is not quite fit my situation. I think your example will hung up the whole VB process until the child process complete. What I am looking for is blocking or delaying other event handler in the same VB project until one method is completed.

[Confucius]

What about using a timer with a boolean?