Send keystrokes to runing process

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  • Start date Start date
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Guest

I am using the below code to run a dos based program. While it is running
you can hit ctrl-c to cancel the process. Does anyone know how I can send
the same keystroke to the already runing process after the below code is
executed?

Dim process As New Process()
Dim FileName As String = "externalprog.exe"
Dim Arguments As String

Arguments = "/c"
process.StartInfo.UseShellExecute = False
process.StartInfo.RedirectStandardOutput = True
process.StartInfo.RedirectStandardError = True
process.StartInfo.CreateNoWindow = True
process.StartInfo.FileName = FileName
process.StartInfo.Arguments = Arguments
process.StartInfo.WorkingDirectory = Application.StartupPath
process.Start()
Return process.StandardOutput.ReadToEnd()
 
Hi Joey,

Based on my understanding, your VB.net application uses Process class to
start another console based application. You wanted to find a way to
generate the console application programmatically just like pressing Ctrl+C
for the console window.

For console application, the Ctrl+C and CTRL+BREAK are 2 special events,
which is not received through the console application's standard input. So
it is impossible to simulate the Ctrl+C effect through standard input
redirect. The official way of generating these 2 events is using
GenerateConsoleCtrlEvent win32 API. However, there is an important
limitation in this API which makes the situation much complex, from MSDN:
"Only those processes in the group that share the same console as the
calling process receive the signal."

So our .Net application must have a console stub window to share the same
console with the application we started. Also, our console stub appliation
must start the application without CREATE_NEW_CONSOLE in CreateProcess which
is encapsulated in .Net Process class.

While .Net Process class always uses CREATE_NEW_CONSOLE(0x10) flag to call
CreateProcess, the new lauched process will be openned in a new console
window, which does not meet the GenerateConsoleCtrlEvent API requirement.

So if you use GenerateConsoleCtrlEvent API with Process class, you will have
no lucky.
The only way is p/invoke win32 CreateProcess API manually, and do not
specify CREATE_NEW_CONSOLE(0x10) flag. Then the new lauched process will
share the same console as the calling process.

I have provided a working code snippet in the thread below:
http://groups.google.com/group/micr...nguages.csharp/msg/ad9f64840af60e6a?hl=en-US&

Hope it helps.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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