CodeItBetter Programming Another VB Programming Blog

'System & API - How to Redirect output from console program to textbox
'Redirects output from console program to textbox.
'Requires two textboxes and one command button.
'Set MultiLine property of Text2 to true.
'
'Note: don't run plain DOS programs with this example under Windows 95,98 and ME, 
'as the program freezes when execution of program is finnished.

Option Explicit
 
Private Declare Function CreatePipe Lib "kernel32" (phReadPipe As Long, phWritePipe As Long, _
    lpPipeAttributes As SECURITY_ATTRIBUTES, ByVal nSize As Long) As Long
Private Declare Sub GetStartupInfo Lib "kernel32" Alias "GetStartupInfoA" _
    (lpStartupInfo As STARTUPINFO)
Private Declare Function CreateProcess Lib "kernel32" Alias "CreateProcessA" _
    (ByVal lpApplicationName As String, ByVal lpCommandLine As String, lpProcessAttributes As Any, _
    lpThreadAttributes As Any, ByVal bInheritHandles As Long, ByVal dwCreationFlags As Long, _
    lpEnvironment As Any, ByVal lpCurrentDriectory As String, lpStartupInfo As STARTUPINFO, _
    lpProcessInformation As PROCESS_INFORMATION) As Long
Private Declare Function SetWindowText Lib "user32" Alias "SetWindowTextA" (ByVal hwnd As Long, _
    ByVal lpString As String) As Long
Private Declare Function ReadFile Lib "kernel32" (ByVal hFile As Long, lpBuffer As Any, _
    ByVal nNumberOfBytesToRead As Long, lpNumberOfBytesRead As Long, lpOverlapped As Any) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, _
    ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
 
Private Type SECURITY_ATTRIBUTES
    nLength As Long
    lpSecurityDescriptor As Long
    bInheritHandle As Long
End Type
 
Private Type PROCESS_INFORMATION
    hProcess As Long
    hThread As Long
    dwProcessId As Long
    dwThreadId As Long
End Type
 
Private Type STARTUPINFO
    cb As Long
    lpReserved As Long
    lpDesktop As Long
    lpTitle As Long
    dwX As Long
    dwY As Long
    dwXSize As Long
    dwYSize As Long
    dwXCountChars As Long
    dwYCountChars As Long
    dwFillAttribute As Long
    dwFlags As Long
    wShowWindow As Integer
    cbReserved2 As Integer
    lpReserved2 As Byte
    hStdInput As Long
    hStdOutput As Long
    hStdError As Long
End Type
 
Private Type OVERLAPPED
    ternal As Long
    ternalHigh As Long
    offset As Long
    OffsetHigh As Long
    hEvent As Long
End Type
 
Private Const STARTF_USESHOWWINDOW = &H1
Private Const STARTF_USESTDHANDLES = &H100
Private Const SW_HIDE = 0
Private Const EM_SETSEL = &HB1
Private Const EM_REPLACESEL = &HC2
 
Private Sub Command1_Click()
    Command1.Enabled = False
    Redirect Text1.Text, Text2
    Command1.Enabled = True
End Sub
 
Private Sub Form_Load()
    Text1.Text = "ping"
End Sub
 
Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
    If Command1.Enabled = False Then Cancel = True
End Sub
 
Sub Redirect(cmdLine As String, objTarget As Object)
    Dim i%, t$
    Dim pa As SECURITY_ATTRIBUTES
    Dim pra As SECURITY_ATTRIBUTES
    Dim tra As SECURITY_ATTRIBUTES
    Dim pi As PROCESS_INFORMATION
    Dim sui As STARTUPINFO
    Dim hRead As Long
    Dim hWrite As Long
    Dim bRead As Long
    Dim lpBuffer(1024) As Byte
    pa.nLength = Len(pa)
    pa.lpSecurityDescriptor = 0
    pa.bInheritHandle = True
 
    pra.nLength = Len(pra)
    tra.nLength = Len(tra)
 
    If CreatePipe(hRead, hWrite, pa, 0) <> 0 Then
        sui.cb = Len(sui)
        GetStartupInfo sui
        sui.hStdOutput = hWrite
        sui.hStdError = hWrite
        sui.dwFlags = STARTF_USESHOWWINDOW Or STARTF_USESTDHANDLES
        sui.wShowWindow = SW_HIDE
        If CreateProcess(vbNullString, cmdLine, pra, tra, True, 0, Null, _
            vbNullString, sui, pi) <> 0 Then
            SetWindowText objTarget.hwnd, ""
            Do
                Erase lpBuffer()
                If ReadFile(hRead, lpBuffer(0), 1023, bRead, ByVal 0&) Then
                    SendMessage objTarget.hwnd, EM_SETSEL, -1, 0
                    SendMessage objTarget.hwnd, EM_REPLACESEL, False, lpBuffer(0)
                    DoEvents
                Else
                    CloseHandle pi.hThread
                    CloseHandle pi.hProcess
                    Exit Do
                End If
                CloseHandle hWrite
            Loop
            CloseHandle hRead
        End If
    End If
End Sub