This article demonstrates attaching a console window to your Visual Basic
application, writing to it, and running another application in the console
If a Visual Basic application is started from a console application, the
operating system automatically detaches it from the console, preventing the
Visual Basic application from interacting with it. This article does not
provide a method to prevent this from happening, but does demonstrate
creating a new console window that your application can interact with. It
also demonstrates running a console application (batch file, in this case)
from Visual Basic, which utilizes the created console.
WARNING: ANY USE BY YOU OF THE CODE PROVIDED IN THIS ARTICLE IS AT YOUR OWN
RISK. Microsoft provides this code "as is" without warranty of any kind,
either express or implied, including but not limited to the implied
warranties of merchantability and/or fitness for a particular purpose.
- Use Notepad to create the following batch file:
and save it as C:\TEST.BAT
- In Visual Basic, create a new project with a form and a module.
- Type the following API declarations in the module:
Declare Function AllocConsole Lib "kernel32" () As Long
Declare Function FreeConsole Lib "kernel32" () As Long
Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) _
Declare Function GetStdHandle Lib "kernel32" (ByVal _
nStdHandle As Long) As Long
Declare Function WriteConsole Lib "kernel32" Alias "WriteConsoleA" _
(ByVal hConsoleOutput As Long, lpBuffer As Any, ByVal _
nNumberOfCharsToWrite As Long, lpNumberOfCharsWritten As Long, _
lpReserved As Any) As Long
Public Const STD_OUTPUT_HANDLE = -11&
- Add a CommandButton to the form and enter the following code:
Dim hConsole As Long
Private Sub Command1_Click()
Dim Result As Long, sOut As String, cWritten As Long
sOut = "Hi There" & vbCrLf
Result = WriteConsole(hConsole, ByVal sOut, Len(sOut), cWritten, _
Private Sub Form_Load()
If AllocConsole() Then
hConsole = GetStdHandle(STD_OUTPUT_HANDLE)
If hConsole = 0 Then MsgBox "Couldn't allocate STDOUT"
MsgBox "Couldn't allocate console"
Private Sub Form_Unload(Cancel As Integer)
- Run the application. A blank console window will appear.
- Click the CommandButton. Both the text in sOut and the output from the
batch file will appear in the console.
- Close the form. The console window will terminate.
- If you run another application in the console, it will run
asynchronously with your Visual Basic application. Output from the two
applications can become interspersed.
- If the console application hasn't terminated prior to your Visual Basic
application closing, the console window will remain open.
- If you close the console window, the Visual Basic EXE will terminate. If
you are in the Visual Basic development environment (IDE), closing the
console window will terminate the IDE and it may hang the console
window. Use the Task Manager to terminate the task.
Article ID: 171654 - Last Review: June 29, 2004 - Revision: 4.1
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