sending text to cmd.exe?

hello, how to send a text to a command prompt?

thanks

You can pass parameters to CMD.exe when you ShellExecute it.

This example will pass the DIR command, enter C:\, and output the directory listing to the file C:\Dir.txt
The /K switch is to keep the DOS window open but you can change it to the /C to close it. Also, SW_HIDE to make
it totally transparent to the user.

VB Code:

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 Sub Command1_Click()
    ShellExecute Me.hwnd, "Open", "C:\Windows\System32\CMD.exe", " /K Dir C:\  > C:\Dir.txt", "C:\", SW_SHOWNORMAL
End Sub

Note: you would want to use the GetSystemDirectory API to dynamically get the directory where the CMD.EXE program is located.

If the window is already open, and you want to send text to it, treat it like any other standard window. I believe the classname is "tty" so pass that through FindWindow and then use PostMessage to send WM_KEYDOWN and WM_KEYUP (or use keybd_event())

Megatron, it was my understanding that the Console window's messagestream was unavailable for sending messages to?

I think the CreatePipe can do something like this :

VB Code:

'Redirects output from console program to textbox.
'Requires two textboxes and one command button.
'Set MultiLine property of Text2 to true.
'
'Original bcx version of this program was made by
' dl <[email protected]>
'VB port was made by Jernej Simoncic <[email protected]>
'Visit Jernejs site at [url]http://www2.arnes.si/~sopjsimo/[/url]
'
'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

I also think that Joacim had posted some better code than this.

So SendMessage will only work if you create the pipe first? I know it doesnt work directly by getting the CMD window handles.
I have read on MSDN somewhere that the message stream is inaccible directly.

Quote:

---

Originally Posted by RobDog888

So SendMessage will only work if you create the pipe first? I know it doesnt work directly by getting the CMD window handles.

---

You shouldn't have to bring pipes into it

The following works for me

VB Code:

Private Declare Function PostMessage Lib "user32.dll" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Private Declare Function FindWindowEx Lib "user32.dll" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
Private Const WM_CHAR As Long = &H102
 
Private Sub Command1_Click()
 
    Dim h As Long
    
    h = FindWindowEx(0, 0, "ConsoleWindowClass", vbNullString)
    If h Then PostMessage h, WM_CHAR, Asc("a"), 0
 
End Sub

What's wrong with doing it this way? :confused:

VB Code:

Private Sub cmdSendCommand_Click()
  Shell(txtCommand.text)
End Sub

Ah, so it does work with PostMessage. How would you do it with SendMessage? WM_SETTEXT?

Rob: Since we're sending WM_CHAR directly, it will work with SendMessage too. If however, we tried to send WM_KEYDOWN and WM_KEYUP, it would fail, since it bypasses the message queue, and thus, the call to TranslateMessage. (But the latter will work with PostMessage).

Short answer: WM_CHAR with either Post/SendMessage will do the trick.

Datacide: Nothing wrong with that (in fact, that's what Rob first suggested). I was just showing another method you can use, if the window is already open.

Thanks Megatron. That really clears things up for me. I thought I was loosing my mind. :D
Will it work with the WM_SETTEXT so you can send a string instead of having to send each char?

Well remember that the command prompt is "all one window" (I.e. the main window is not separated from the text entry part, like Notepad is) so sending WM_SETTEXT will only change the window's titlebar text.

To send an entire string, you could write a function that cycles through each character in the string, and send a WM_CHAR message for each letter.

I was hoping there was a way to do it by string instead of char but at least I know there is a way now. That make a little more sense now Mega. Thanks :thumb: