This article demonstrates a technique you can use to send keystrokes to a
Microsoft MS-DOS-based application from a Microsoft Visual Basic
application. Note that with Visual Basic 4.0, 16-bit, this method does not work on Windows NT or Windows 2000.
The Visual Basic for Windows SendKeys function can send keystrokes to the
currently active window as if the keystrokes had been typed at the
keyboard. Although it is not possible to send keystrokes to an
application that is not based on Windows by using SendKeys directly, you
can place text on the Clipboard and use the SendKeys function to paste that
text into an MS-DOS-based application that is running in a window or
minimized as an icon.
To run an MS-DOS-based application in a window, you must be running in
Windows 386 enhanced mode. You must also make sure that the MS-DOS-based
application's .PIF file has been set to display the application in a window
rather than full screen. Use the Windows PIF Editor to make this
modification, if necessary.
The following example demonstrates how to send keystrokes to an MS-DOS
session running in a window:
- Start an MS-DOS session running in a window.
- Start Visual Basic for Windows and start a new project.
- Enter the following into the general declarations section of the form:
- Put two labels on the form. Change the first label's caption to
"MS-DOS App Title." Change the second label's caption to "Keys to send."
- Put two text boxes on the form next to each of the labels. Delete the
default contents of these text boxes. These controls are used to allow
the user to enter the MS-DOS-based application's window title and the
keystrokes to send to it. Change the Name property of these text
boxes to "DosTitle" and "DosKeys" respectively.
- Put a command button on the form, and change its caption to "Send keys."
- Add the following code to the Command1 button click event procedure:
If the text that you send is the DIR command or another command that
takes time, the AppActivate call immediately following the SendKeys
call can interrupt the processing. The AppActivate call should be
placed in a timer with the appropriate interval set, and the timer
should be enabled in the command_click procedure. The timer should
be disabled before exiting the timer.
Private Sub Command1_Click()
'Ensure that progname is set to the titlebar of Visual Basic while
progname = "Project1 - Microsoft Visual Basic [run]"
clipboard.SetText DosKeys.Text + Chr$(13) ' Append a <CR>.
SendKeys "% ep", 1
- Run the program.
- Enter the window title of the MS-DOS-based application into the DosTitle
text box. The default window title for an MS-DOS session is
- Enter the keystrokes to send into the DosKeys text box (for
- Click the Send Keys button. The keystrokes are sent to the
Clipboard and then pasted into the MS-DOS window.
To use this technique in a compiled Visual Basic for Windows program,
change the progname assignment from "Microsoft Visual Basic" to the
executable file name. Also, to see the text being placed onto the
Clipboard, open the Windows Clipboard viewer.
Article ID: 142819 - Last Review: July 13, 2004 - Revision: 1.1
- Microsoft Visual Basic 4.0 Professional Edition
- Microsoft Visual Basic 4.0 16-bit Enterprise Edition
Retired KB Content Disclaimer
This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.