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I'm writing a wrapper class for a command line executable. This exe accepts input from stdin until I hit Ctrl+C in the command prompt shell, in which case it prints output to stdout based on the input. I want to simulate that Ctrl+C press in C# code, sending the kill command to a .NET Process object. I've tried calling Process.Kill(), but that doesn't seem to give me anything in the process's StandardOutput StreamReader. Might there be anything I'm not doing right? Here's the code I'm trying to use:
ProcessStartInfo info = new ProcessStartInfo(exe, args);
info.RedirectStandardError = true;
info.RedirectStandardInput = true;
info.RedirectStandardOutput = true;
info.UseShellExecute = false;
Process p = Process.Start(info);
p.StandardInput.AutoFlush = true;
p.StandardInput.WriteLine(scriptcode);
p.Kill();
string error = p.StandardError.ReadToEnd();
if (!String.IsNullOrEmpty(error))
{
throw new Exception(error);
}
string output = p.StandardOutput.ReadToEnd();
The output is always empty, even though I get data back from stdout when I run the exe manually.
Edit: This is C# 2.0 by the way.
Despite the fact that using GenerateConsoleCtrlEvent() for sending Ctrl+C signal is the right answer, it needs significant clarification to get it to work in different .NET application types.
If your .NET application doesn't use its own console (Windows Forms/WPF/Windows Service/ASP.NET), the basic flow is:
Attach the main .NET process to the console of the process that you want to signal with Ctrl+C.
Prevent the main .NET process from stopping because of Ctrl+C event by disabling handling of the signal with SetConsoleCtrlHandler().
Generate the console event for the current console with GenerateConsoleCtrlEvent() (processGroupId should be zero! The answer with code that sends p.SessionId will not work and is incorrect).
Wait for the signaled process to respond (e.g. by waiting for it to exit)
Restore Ctrl+C handling by main process and disconnect from console.
The following code snippet illustrates how to do that:
Process p;
if (AttachConsole((uint)p.Id)) {
SetConsoleCtrlHandler(null, true);
try {
if (!GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0))
return false;
p.WaitForExit();
} finally {
SetConsoleCtrlHandler(null, false);
FreeConsole();
}
return true;
}
where SetConsoleCtrlHandler(), FreeConsole(), AttachConsole() and GenerateConsoleCtrlEvent() are native WinAPI methods:
internal const int CTRL_C_EVENT = 0;
[DllImport("kernel32.dll")]
internal static extern bool GenerateConsoleCtrlEvent(uint dwCtrlEvent, uint dwProcessGroupId);
[DllImport("kernel32.dll", SetLastError = true)]
internal static extern bool AttachConsole(uint dwProcessId);
[DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)]
internal static extern bool FreeConsole();
[DllImport("kernel32.dll")]
static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate HandlerRoutine, bool Add);
// Delegate type to be used as the Handler Routine for SCCH
delegate Boolean ConsoleCtrlDelegate(uint CtrlType);
Note that waiting for the targeted process to respond, typically by waiting for the process to exit, is critical. Otherwise, the Ctrl+C signal will remain in the current process's input queue and when handling is restored by the second call to SetConsoleCtrlHandler(), that signal will terminate the current process, rather than the targeted one.
Things become more complex if you need to send Ctrl+C from .NET console application. The above approach will not work because AttachConsole() returns false in this case (the main console app already has a console). It is possible to call FreeConsole() before AttachConsole() call, but doing so will result in the original .NET app console being lost, which is not acceptable in most cases.
Here is my solution for this case; it works and has no side effects for the .NET main process console:
Create small supporting .NET console program that accepts process ID from command line arguments, loses its own console with FreeConsole() before the AttachConsole() call and sends Ctrl+C to the target process with code mentioned above.
The main .NET console process just invokes this utility in a new process when it needs to send Ctrl+C to another console process.
I've actually just figured out the answer. Thank you both for your answers, but it turns out that all i had to do was this:
p.StandardInput.Close()
which causes the program I've spawned to finish reading from stdin and output what i need.
#alonl: The user is attempting to wrap a command-line program. Command-line programs don't have message pumps unless they are specifically created, and even if that was the case, Ctrl+C doesn't have the same semantics in a Windows-environment application (copy, by default) as it does in a command-line environment (Break).
I threw this together. CtrlCClient.exe simply calls Console.ReadLine() and waits:
static void Main(string[] args)
{
ProcessStartInfo psi = new ProcessStartInfo("CtrlCClient.exe");
psi.RedirectStandardInput = true;
psi.RedirectStandardOutput = true;
psi.RedirectStandardError = true;
psi.UseShellExecute = false;
Process proc = Process.Start(psi);
Console.WriteLine("{0} is active: {1}", proc.Id, !proc.HasExited);
proc.StandardInput.WriteLine("\x3");
Console.WriteLine(proc.StandardOutput.ReadToEnd());
Console.WriteLine("{0} is active: {1}", proc.Id, !proc.HasExited);
Console.ReadLine();
}
My output seems to do what you want:
4080 is active: True
4080 is active: False
Hope that helps!
(To clarify: \x3 is the hex escape sequence for the hex character 3, which is Ctrl+C. It's not just a magic number. ;) )
Ok, here is a solution.
The way to send the Ctrl-C signal is with GenerateConsoleCtrlEvent. HOWEVER, this call takes a processGroupdID parameter, and sends the Ctrl-C signal to all processes in the group. This would be fine if it weren't for the fact that there is no way spawn child process in .net that is in a different process group than you (the parent) are in. So, when you send the GenerateConsoleCtrlEvent, both the child AND YOU (THE PARENT) GET IT. So, you need to capture the Ctrl-C event in the parent too, and then determine if you ned to ignore it not.
In my case, I want the parent to be able to handle Ctrl-C events also, so I need to distnguish between Ctrl-C events sent by the user on the console, and those sent by the parent process to the child. I do this by just hackishly setting/unsetting a boolean flag while send the Ctrl-C to the child, and then checking for this flag in the parent's Ctrl-C event handler (ie. if send Ctrl-C to child, then ignore.)
So, the code would look something like this:
//import in the declaration for GenerateConsoleCtrlEvent
[DllImport("kernel32.dll", SetLastError=true)]
static extern bool GenerateConsoleCtrlEvent(ConsoleCtrlEvent sigevent, int dwProcessGroupId);
public enum ConsoleCtrlEvent
{
CTRL_C = 0,
CTRL_BREAK = 1,
CTRL_CLOSE = 2,
CTRL_LOGOFF = 5,
CTRL_SHUTDOWN = 6
}
//set up the parents CtrlC event handler, so we can ignore the event while sending to the child
public static volatile bool SENDING_CTRL_C_TO_CHILD = false;
static void Console_CancelKeyPress(object sender, ConsoleCancelEventArgs e)
{
e.Cancel = SENDING_CTRL_C_TO_CHILD;
}
//the main method..
static int Main(string[] args)
{
//hook up the event handler in the parent
Console.CancelKeyPress += new ConsoleCancelEventHandler(Console_CancelKeyPress);
//spawn some child process
System.Diagnostics.ProcessStartInfo psi = new System.Diagnostics.ProcessStartInfo();
psi.Arguments = "childProcess.exe";
Process p = new Process();
p.StartInfo = psi;
p.Start();
//sned the ctrl-c to the process group (the parent will get it too!)
SENDING_CTRL_C_TO_CHILD = true;
GenerateConsoleCtrlEvent(ConsoleCtrlEvent.CTRL_C, p.SessionId);
p.WaitForExit();
SENDING_CTRL_C_TO_CHILD = false;
//note that the ctrl-c event will get called on the parent on background thread
//so you need to be sure the parent has handled and checked SENDING_CTRL_C_TO_CHILD
already before setting it to false. 1000 ways to do this, obviously.
//get out....
return 0;
}
FWIW, in my case, what I wanted is, from a console process, create a child console process (ffmpeg.exe for that matter) and support clean CTRL-C handling in my process and in the child process (ffmpreg exits normally when CTRL-C is pressed which is a nice feature I wanted to keep working)
None of the solution I found here were working, so I just interop'd Windows' CreateProcess function and it just works w/o any effort, CTRL-C is automatically received by the child app and by the parent app, input and output streams are shared, etc. I was not able to reproduce that kind of code using the standard .NET Process class:
static void RunFFMpeg(string arguments)
{
var startup = new STARTUPINFO();
startup.cb = Marshal.SizeOf<STARTUPINFO>();
if (!CreateProcess(null, "ffmpeg.exe " + arguments, IntPtr.Zero, IntPtr.Zero, false, 0, IntPtr.Zero, null, ref startup, out var info))
throw new Win32Exception(Marshal.GetLastWin32Error());
CloseHandle(info.hProcess);
CloseHandle(info.hThread);
var process = Process.GetProcessById(info.dwProcessId);
Console.CancelKeyPress += (s, e) =>
{
process.WaitForExit();
Console.WriteLine("Abort.");
// end of program is here
};
process.WaitForExit();
Console.WriteLine("Exit.");
}
[StructLayout(LayoutKind.Sequential)]
private struct PROCESS_INFORMATION
{
public IntPtr hProcess;
public IntPtr hThread;
public int dwProcessId;
public int dwThreadId;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
private struct STARTUPINFO
{
public int cb;
public string lpReserved;
public string lpDesktop;
public string lpTitle;
public int dwX;
public int dwY;
public int dwXSize;
public int dwYSize;
public int dwXCountChars;
public int dwYCountChars;
public int dwFillAttribute;
public int dwFlags;
public short wShowWindow;
public short cbReserved2;
public IntPtr lpReserved2;
public IntPtr hStdInput;
public IntPtr hStdOutput;
public IntPtr hStdError;
}
[DllImport("kernel32")]
private static extern bool CloseHandle(IntPtr hObject);
[DllImport("kernel32", SetLastError = true, CharSet = CharSet.Unicode)]
private static extern bool CreateProcess(
string lpApplicationName,
string lpCommandLine,
IntPtr lpProcessAttributes,
IntPtr lpThreadAttributes,
bool bInheritHandles,
int dwCreationFlags,
IntPtr lpEnvironment,
string lpCurrentDirectory,
ref STARTUPINFO lpStartupInfo,
out PROCESS_INFORMATION lpProcessInformation);
Try actually sending the Key Combination Ctrl+C, instead of directly terminating the process:
[DllImport("user32.dll")]
public static extern int SendMessage(
int hWnd, // handle to destination window
uint Msg, // message
long wParam, // first message parameter
long lParam // second message parameter
);
Look it up on the MSDN, you should find what you need there in order to send the Ctrl+Key combination...
I know that the message you need for sending Alt+Key is WM_SYSTEMKEYDOWN and WM_SYSTEMKEYUP, can't tell you about Ctrl...
I have an application that spawns multiples threads, one of which runs an iPerf executable which is used to monitor network reliability. This process will run indefinitely, until the user attempts to close the window. This is where the issue comes in. I am trying to shut that process down gracefully so that the iPerf server does not get hung up, but I can not seem to get this working. I can shut it down just fine if I run the command manually from a command prompt and press Ctrl+c, but this does not seem to be easily done programmatically.
I have tried multiple things, including process.Kill(); or process.StandardInput.Close() or even process.StandardInput.WriteLine("\x3"); but none of these seem to send a graceful shutdown message to the process. process.Kill(); causes the server to hang or fail to start up the next time, and the other two options do not stop the server at all. But the manual ctrl+c works just fine.
Here is a snippet of my code:
iperf_proc = new Process();
iperf_proc.StartInfo.FileName = Application.StartupPath + ".\\iperf3.exe";
String argumentStr = " -c " + test_data.host + " -t 0";
iperf_proc.StartInfo.Arguments = argumentStr;
iperf_proc.StartInfo.UseShellExecute = false;
iperf_proc.StartInfo.RedirectStandardOutput = true;
iperf_proc.StartInfo.RedirectStandardInput = true;
iperf_proc.StartInfo.RedirectStandardError = true;
iperf_proc.Start();
iperfRunning = true;
iperf_proc.BeginOutputReadLine();
iperf_proc.BeginErrorReadLine();
while (false == iperf_proc.HasExited)
{
if (true == processCancelled)
{
iperf_proc.StandardInput.Close(); // Doesn't Work!
iperf_proc.StandardInput.WriteLine("\x3"); // Doesn't Work!
iperf_proc.StandardInput.Flush(); // Doesn't Work!
}
}
iperf_proc.WaitForExit();
Any help is greatly appreciated. Thank you!
UPDATE:
Based on the suggestion from Hans in the comment, I tried adding some stuff to the code to get the ctrl+c event sent over.
[DllImport("kernel32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool GenerateConsoleCtrlEvent(uint dwCtrlEvent, uint dwProcessGroupId);
private enum CtrlEvents
{
CTRL_C_EVENT = 0,
CTRL_BREAK_EVENT = 1
}
private void closeBtn_Click(object sender, EventArgs e)
{
processCancelled = true;
//iperf_proc.CloseMainWindow();
bool succeeded = GenerateConsoleCtrlEvent((uint)CtrlEvents.CTRL_C_EVENT, (uint)iperf_proc.Id);
}
This did not work at all. The process is still running and it does the function added returns false. I did check that the process id being passed matches the id of the process in task manager. That all is fine, but the GenerateConsoleCtrlEvent function returns false. Any idea why this may be?
BeginOutputReadLine
Link describes how to do exactly what you are looking for in the example.
Why not use the built in Exited event to wait on so you are not blocking? Especially if you are spawning multiple threads. If you want to block then WaitForExit() is available as well.
if (true == processCancelled)
{
iperf_proc.StandardInput.Close(); // Doesn't Work!
iperf_proc.StandardInput.WriteLine("\x3"); // Doesn't Work!
iperf_proc.StandardInput.Flush(); // Doesn't Work!
}
If you close the standard input, how are you going to write/flush it?
After you have WaitForExit() you also need to Close()
in my application i m open Wireshark process and start capturing packts, in the UI i have Start button who start the capturing and Stop button who stop capturing and i am doing this by killing my wireshark process.
my question is if i am close my application in the middle of the capturing but nor with my Stop button my Wireshark process continue to run, how can i handle this situation and make sure that my process will close if my application crash or someone close it in the middle of capturing
public void startCapturing()
{
ThreadStart tStarter = delegate { openAdapterForStatistics(_device); };
Thread thread = new Thread(tStarter);
thread.IsBackground = true;
thread.Start();
ProcessStartInfo tsharkStartInfo = new ProcessStartInfo();
tsharkStartInfo.FileName = _tshark;
tsharkStartInfo.RedirectStandardOutput = true;
tsharkStartInfo.RedirectStandardError = true;
tsharkStartInfo.RedirectStandardInput = true;
tsharkStartInfo.UseShellExecute = false;
tsharkStartInfo.CreateNoWindow = true;
tsharkStartInfo.Arguments = string.Format(" -i " + _interfaceNumber + " -s " + _packetLimitSize + " -w " + _pcapPath);
_tsharkProcess.StartInfo = tsharkStartInfo;
_tsharkProcess.ErrorDataReceived += _cmdProcess_ErrorDataReceived;
_tsharkProcess.OutputDataReceived += tshark_OutputDataReceived;
_tsharkProcess.EnableRaisingEvents = true;
_tsharkProcess.Start();
_tsharkProcess.BeginOutputReadLine();
_tsharkProcess.BeginErrorReadLine();
FileInfo fileInfo = new FileInfo(_pcapPath);
string directoryName = fileInfo.DirectoryName;
DirectoryInfo directoryInfo = new DirectoryInfo(directoryName);
FileInfo[] dirs = directoryInfo.GetFiles();
_file = dirs.FirstOrDefault(f => f.Name.Equals(fileInfo.Name));
_tsharkProcess.WaitForExit();
}
Assuming you're handling exceptions using try-catch, you can make sure the Wireshark process is closed in the finally block at the end of your topmost try-catch statement. From the MSDN documentation:
"The finally block is useful for cleaning up any resources allocated in the try block. Control is always passed to the finally block regardless of how the try block exits."
For example:
try
{
// Your application's code.
}
catch( Exception )
{
// Handle, log, whatever.
}
finally
{
// Make sure Wireshark process is killed.
}
The code in the finally block will always get executed whether or not there was an exception.
You can't be 100% sure. If your application crashes in a 'civilized' manner, you can close the Wireshark process (much like #jebar8 suggested). Unfortunately, your application could crash in a way that doesn't run your finally code (if it's out of memory or your main thread is out of stack space, for example).
If you want to take that into account as well, you need a third process. Write up a small program that will launch your application and monitor it. If your application process disappears, your monitoring process can then kill Wirehsark is it's alive. Since the monitoring program is a short and simple one, the chance of it crashing unexpectedly are very slim.
I am starting an executable using this code:
Process proc = new Process();
proc.StartInfo.FileName = executablePath;
proc.Start();
proc.WaitForInputIdle();
after this calling proc.Id it gives me some integer, which is not real process ID. In the task manager there is another ID for this process and also I am using MS UI Automation to access this application, which also returns the same ID as in task manager. So my question is how can I get the real process ID of started process?
UPDATE
I found out that on Windows 7 it works fine and returns me the right ID, but not on Windows XP. What can be the reason?
SCENARIO
The scenario of the application is the following. I have a running embedded HTTP server, which is implemented not by me, (here is the source). The client connects to the web server and sends a request to run a program. In the request handler of my server I am just using Process.start() to start the requested application. As a web server the program creates threads for every client session connected to it (I assume so, as I didn't wrote it). Can this somehow help to identify the problem as it exists only on Windows XP X86 Service Pack 3?
An example of how I did it:
bool started = false;
var p = new Process();
p.StartInfo.FileName = "notepad.exe";
started = p.Start();
try {
var procId = p.Id;
Console.WriteLine("ID: " + procId);
}
catch(InvalidOperationException)
{
started = false;
}
catch(Exception ex)
{
started = false;
}
Otherwise, try using handles like this:
Using handlers
Getting handler
hWnd = (int) process.MainWindowHandle;
int processId;
GetWindowThreadProcessId(hWnd, out processId);
[DllImport("user32")]
static extern int GetWindowThreadProcessId(IntPtr hWnd, out int processId);
Side note:
What happens if you get the array of process and iterate over them and compare the PIDs?
Process[] p = Process.GetProcessesByName( "testprogram" );
foreach(var proc in p)
Console.WriteLine("Found: "+proc.Id == myExpectedProcId);
This:
using (Process process = Process.Start("notepad.exe"))
{
process.WaitForInputIdle();
Console.WriteLine(process.Id);
}
Actually works for me:
http://pasteboard.s3.amazonaws.com/images/1350293463417532.png
Task Manager:
http://pasteboard.s3.amazonaws.com/images/1350293536498959.png
My thoughts:
Actually your process starts another process and you are trying to get ID of some kind of launcher. (It can start itself by the way).
Below also returns the PID of a process
Process[] p = Process.GetProcessesByName("YourProcessName");
Now you can get process Id by using p[i].Id;
I'm just trying to guess here, since it's difficult to understand what's really happening without seeing the real code. Anyway, you mentioned Trhreads in one of your comment. Is it possible that you have a single variable proc of type Process which is initialized in your main thread, and then the process is started in a different Thread?
If this is the case, maybe the process is started more than once, and you get the PID of just one of them. The only way I was able to reproduce your case is this one:
private Process proc;
private List<int> pids = new List<int>();
public void StartProc()
{
// this tries to simulate what you're doing. Starts the process, then
// wait to be sure that the second process starts, then kill proc
proc.Start();
pids.Add(proc.Id);
Thread.Sleep(300);
try
{
proc.Kill();
}
catch {}
}
// the method returns the PID of the process
public int Test()
{
proc = new Process();
proc.StartInfo.FileName = #"notepad.exe";
for (int i = 0; i < 2; i++)
{
Thread t = new Thread(StartProc);
t.Start();
Thread.Sleep(200);
}
Thread.Sleep(500);
return proc.Id;
}
When you executes Test, you should see a single active Notepad, and the PID returned by the method is different by the one showed by the Task Manager. But if you take a look at the pids List, you should see that the Task Manager PID is the first element in the list, and the one returned by the method is the second one.
Is it possible that you have done something similar?
I'm writing a wrapper class for a command line executable. This exe accepts input from stdin until I hit Ctrl+C in the command prompt shell, in which case it prints output to stdout based on the input. I want to simulate that Ctrl+C press in C# code, sending the kill command to a .NET Process object. I've tried calling Process.Kill(), but that doesn't seem to give me anything in the process's StandardOutput StreamReader. Might there be anything I'm not doing right? Here's the code I'm trying to use:
ProcessStartInfo info = new ProcessStartInfo(exe, args);
info.RedirectStandardError = true;
info.RedirectStandardInput = true;
info.RedirectStandardOutput = true;
info.UseShellExecute = false;
Process p = Process.Start(info);
p.StandardInput.AutoFlush = true;
p.StandardInput.WriteLine(scriptcode);
p.Kill();
string error = p.StandardError.ReadToEnd();
if (!String.IsNullOrEmpty(error))
{
throw new Exception(error);
}
string output = p.StandardOutput.ReadToEnd();
The output is always empty, even though I get data back from stdout when I run the exe manually.
Edit: This is C# 2.0 by the way.
Despite the fact that using GenerateConsoleCtrlEvent() for sending Ctrl+C signal is the right answer, it needs significant clarification to get it to work in different .NET application types.
If your .NET application doesn't use its own console (Windows Forms/WPF/Windows Service/ASP.NET), the basic flow is:
Attach the main .NET process to the console of the process that you want to signal with Ctrl+C.
Prevent the main .NET process from stopping because of Ctrl+C event by disabling handling of the signal with SetConsoleCtrlHandler().
Generate the console event for the current console with GenerateConsoleCtrlEvent() (processGroupId should be zero! The answer with code that sends p.SessionId will not work and is incorrect).
Wait for the signaled process to respond (e.g. by waiting for it to exit)
Restore Ctrl+C handling by main process and disconnect from console.
The following code snippet illustrates how to do that:
Process p;
if (AttachConsole((uint)p.Id)) {
SetConsoleCtrlHandler(null, true);
try {
if (!GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0))
return false;
p.WaitForExit();
} finally {
SetConsoleCtrlHandler(null, false);
FreeConsole();
}
return true;
}
where SetConsoleCtrlHandler(), FreeConsole(), AttachConsole() and GenerateConsoleCtrlEvent() are native WinAPI methods:
internal const int CTRL_C_EVENT = 0;
[DllImport("kernel32.dll")]
internal static extern bool GenerateConsoleCtrlEvent(uint dwCtrlEvent, uint dwProcessGroupId);
[DllImport("kernel32.dll", SetLastError = true)]
internal static extern bool AttachConsole(uint dwProcessId);
[DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)]
internal static extern bool FreeConsole();
[DllImport("kernel32.dll")]
static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate HandlerRoutine, bool Add);
// Delegate type to be used as the Handler Routine for SCCH
delegate Boolean ConsoleCtrlDelegate(uint CtrlType);
Note that waiting for the targeted process to respond, typically by waiting for the process to exit, is critical. Otherwise, the Ctrl+C signal will remain in the current process's input queue and when handling is restored by the second call to SetConsoleCtrlHandler(), that signal will terminate the current process, rather than the targeted one.
Things become more complex if you need to send Ctrl+C from .NET console application. The above approach will not work because AttachConsole() returns false in this case (the main console app already has a console). It is possible to call FreeConsole() before AttachConsole() call, but doing so will result in the original .NET app console being lost, which is not acceptable in most cases.
Here is my solution for this case; it works and has no side effects for the .NET main process console:
Create small supporting .NET console program that accepts process ID from command line arguments, loses its own console with FreeConsole() before the AttachConsole() call and sends Ctrl+C to the target process with code mentioned above.
The main .NET console process just invokes this utility in a new process when it needs to send Ctrl+C to another console process.
I've actually just figured out the answer. Thank you both for your answers, but it turns out that all i had to do was this:
p.StandardInput.Close()
which causes the program I've spawned to finish reading from stdin and output what i need.
#alonl: The user is attempting to wrap a command-line program. Command-line programs don't have message pumps unless they are specifically created, and even if that was the case, Ctrl+C doesn't have the same semantics in a Windows-environment application (copy, by default) as it does in a command-line environment (Break).
I threw this together. CtrlCClient.exe simply calls Console.ReadLine() and waits:
static void Main(string[] args)
{
ProcessStartInfo psi = new ProcessStartInfo("CtrlCClient.exe");
psi.RedirectStandardInput = true;
psi.RedirectStandardOutput = true;
psi.RedirectStandardError = true;
psi.UseShellExecute = false;
Process proc = Process.Start(psi);
Console.WriteLine("{0} is active: {1}", proc.Id, !proc.HasExited);
proc.StandardInput.WriteLine("\x3");
Console.WriteLine(proc.StandardOutput.ReadToEnd());
Console.WriteLine("{0} is active: {1}", proc.Id, !proc.HasExited);
Console.ReadLine();
}
My output seems to do what you want:
4080 is active: True
4080 is active: False
Hope that helps!
(To clarify: \x3 is the hex escape sequence for the hex character 3, which is Ctrl+C. It's not just a magic number. ;) )
Ok, here is a solution.
The way to send the Ctrl-C signal is with GenerateConsoleCtrlEvent. HOWEVER, this call takes a processGroupdID parameter, and sends the Ctrl-C signal to all processes in the group. This would be fine if it weren't for the fact that there is no way spawn child process in .net that is in a different process group than you (the parent) are in. So, when you send the GenerateConsoleCtrlEvent, both the child AND YOU (THE PARENT) GET IT. So, you need to capture the Ctrl-C event in the parent too, and then determine if you ned to ignore it not.
In my case, I want the parent to be able to handle Ctrl-C events also, so I need to distnguish between Ctrl-C events sent by the user on the console, and those sent by the parent process to the child. I do this by just hackishly setting/unsetting a boolean flag while send the Ctrl-C to the child, and then checking for this flag in the parent's Ctrl-C event handler (ie. if send Ctrl-C to child, then ignore.)
So, the code would look something like this:
//import in the declaration for GenerateConsoleCtrlEvent
[DllImport("kernel32.dll", SetLastError=true)]
static extern bool GenerateConsoleCtrlEvent(ConsoleCtrlEvent sigevent, int dwProcessGroupId);
public enum ConsoleCtrlEvent
{
CTRL_C = 0,
CTRL_BREAK = 1,
CTRL_CLOSE = 2,
CTRL_LOGOFF = 5,
CTRL_SHUTDOWN = 6
}
//set up the parents CtrlC event handler, so we can ignore the event while sending to the child
public static volatile bool SENDING_CTRL_C_TO_CHILD = false;
static void Console_CancelKeyPress(object sender, ConsoleCancelEventArgs e)
{
e.Cancel = SENDING_CTRL_C_TO_CHILD;
}
//the main method..
static int Main(string[] args)
{
//hook up the event handler in the parent
Console.CancelKeyPress += new ConsoleCancelEventHandler(Console_CancelKeyPress);
//spawn some child process
System.Diagnostics.ProcessStartInfo psi = new System.Diagnostics.ProcessStartInfo();
psi.Arguments = "childProcess.exe";
Process p = new Process();
p.StartInfo = psi;
p.Start();
//sned the ctrl-c to the process group (the parent will get it too!)
SENDING_CTRL_C_TO_CHILD = true;
GenerateConsoleCtrlEvent(ConsoleCtrlEvent.CTRL_C, p.SessionId);
p.WaitForExit();
SENDING_CTRL_C_TO_CHILD = false;
//note that the ctrl-c event will get called on the parent on background thread
//so you need to be sure the parent has handled and checked SENDING_CTRL_C_TO_CHILD
already before setting it to false. 1000 ways to do this, obviously.
//get out....
return 0;
}
FWIW, in my case, what I wanted is, from a console process, create a child console process (ffmpeg.exe for that matter) and support clean CTRL-C handling in my process and in the child process (ffmpreg exits normally when CTRL-C is pressed which is a nice feature I wanted to keep working)
None of the solution I found here were working, so I just interop'd Windows' CreateProcess function and it just works w/o any effort, CTRL-C is automatically received by the child app and by the parent app, input and output streams are shared, etc. I was not able to reproduce that kind of code using the standard .NET Process class:
static void RunFFMpeg(string arguments)
{
var startup = new STARTUPINFO();
startup.cb = Marshal.SizeOf<STARTUPINFO>();
if (!CreateProcess(null, "ffmpeg.exe " + arguments, IntPtr.Zero, IntPtr.Zero, false, 0, IntPtr.Zero, null, ref startup, out var info))
throw new Win32Exception(Marshal.GetLastWin32Error());
CloseHandle(info.hProcess);
CloseHandle(info.hThread);
var process = Process.GetProcessById(info.dwProcessId);
Console.CancelKeyPress += (s, e) =>
{
process.WaitForExit();
Console.WriteLine("Abort.");
// end of program is here
};
process.WaitForExit();
Console.WriteLine("Exit.");
}
[StructLayout(LayoutKind.Sequential)]
private struct PROCESS_INFORMATION
{
public IntPtr hProcess;
public IntPtr hThread;
public int dwProcessId;
public int dwThreadId;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
private struct STARTUPINFO
{
public int cb;
public string lpReserved;
public string lpDesktop;
public string lpTitle;
public int dwX;
public int dwY;
public int dwXSize;
public int dwYSize;
public int dwXCountChars;
public int dwYCountChars;
public int dwFillAttribute;
public int dwFlags;
public short wShowWindow;
public short cbReserved2;
public IntPtr lpReserved2;
public IntPtr hStdInput;
public IntPtr hStdOutput;
public IntPtr hStdError;
}
[DllImport("kernel32")]
private static extern bool CloseHandle(IntPtr hObject);
[DllImport("kernel32", SetLastError = true, CharSet = CharSet.Unicode)]
private static extern bool CreateProcess(
string lpApplicationName,
string lpCommandLine,
IntPtr lpProcessAttributes,
IntPtr lpThreadAttributes,
bool bInheritHandles,
int dwCreationFlags,
IntPtr lpEnvironment,
string lpCurrentDirectory,
ref STARTUPINFO lpStartupInfo,
out PROCESS_INFORMATION lpProcessInformation);
Try actually sending the Key Combination Ctrl+C, instead of directly terminating the process:
[DllImport("user32.dll")]
public static extern int SendMessage(
int hWnd, // handle to destination window
uint Msg, // message
long wParam, // first message parameter
long lParam // second message parameter
);
Look it up on the MSDN, you should find what you need there in order to send the Ctrl+Key combination...
I know that the message you need for sending Alt+Key is WM_SYSTEMKEYDOWN and WM_SYSTEMKEYUP, can't tell you about Ctrl...