For one of my implementations I am working on a tool that is supposed to send/retrieve commands/results to/from the cmd window. Everything works fine but the Use case below fails to do anything. It seems as if my application is waiting for something (instead of displaying the result)
From my tool I navigate to the python folder . From the python folder I try to launch python.exe but at this point, my editor does not do anything. it simply keeps on waiting.
For your kind consideration I am also linking the video here. It would be easier for you guys to understand what I am trying to say.
View the Video here (on youtube)
I am also attaching the code that I currently have.
ProcessStartInfo info = new ProcessStartInfo("cmd.exe");
string argument = null;
if (!string.IsNullOrEmpty(startingDirectory) && System.IO.Directory.Exists(startingDirectory))
{
argument += #"cd\";
}
else
{
argument += "\"";
}
info.Arguments = argument;
info.CreateNoWindow = true;
info.RedirectStandardError = true;
info.RedirectStandardInput = true;
info.RedirectStandardOutput = true;
info.UseShellExecute = false;
this.shellProcess = System.Diagnostics.Process.Start(info);
this.shellProcess.EnableRaisingEvents = true;
//this.InputStream.AutoFlush = true;
this.shellProcess.Exited += new EventHandler(ProcessExited);
this.ErrorBeginRead();
this.OutputBeginRead();
private void OutputBeginRead()
{
this.shellProcess.StandardOutput.BaseStream.BeginRead(outputBuffer, 0, outputBuffer.Length, new AsyncCallback(this.OnOutputInput), this.shellProcess);
}
private void ErrorBeginRead()
{
this.shellProcess.StandardError.BaseStream.BeginRead(errorBuffer, 0, errorBuffer.Length, new AsyncCallback(this.OnErrorInput), this.shellProcess);
}
Thank you !
EDIT:
Launching python is just an example. I need to use the same method for other normal cmd line commands as well.It would be nice, if somebody can point what i am doing wrong with the code that I have or what I must do , in order to achieve the intended functionality.
EDIT 2 : The normal cmd commands are working perfectly. The command line tools like python,perl are not working .
Edit 3 : So I managed to do move a wee bit forward following Jamie's suggestions. The ui is not "hanging" anymore. but when i access the python interpreter , the interpreter's output is still not visible in my tool. Any suggestions why that might be happening ?
You cannot send commands to a shell this way. The string in info.Arguments is the arguments provided to the program on the command line. If you want the cmd.exe shell to execute a series of command and then quit you will have to provide the /c argument. If you have multiple commands that you want it to perform you will either have to put the commands in a batch file and execute that or enclose them in quotes and separate them with &&, i.e. info.Arguments = #"/c ""cd \ && dir""";. Your other issue with never returning is that cmd.exe opens in interactive mode by default when it is executed without any, or proper, arguments. The /c option tells cmd.exe to execute the relevant commands and then quit.
Additionally, interpreters like python and perl sometimes have weird behaviors when launched directly from ProcessStartInfo. If info.Arguments = #"""MyPerlProgram.pl"""; with perl.exe doesn't work, you may find it necessary to launch them inside cmd.exe to get normal behavior out of them, i.e. info.Arguments = #"/c ""perl.exe ""MyPerlProgram.pl""""";.
See Cmd and ProcessStartInfo.Arguments Property.
To answer your Edit 3 problem, you're probably not correctly hooking into the outputs. Instead of trying to hook the StreamReader's BaseStream, hook the OutputDataReceived event with this.shellProcess.OutputDataReceived += ProcessOutputHandler; before you call Start where ProcessOutputHandler has a signature like public static void ProcessOutputHandler(object sendingProcess, DataReceivedEventArgs outLine). Immediately after calling Start, call this.shellProcess.BeginOutputReadLine();. The process is similar for the error ouput as well. See Process.BeginOutputReadLine Method and Process.BeginErrorReadLine Method for more details.
If you still have a problem, what do you get if you just try process.StartInfo.Arguments = #"/c ""python.exe -c ""import sys; print 'Test.';""""";?
Also, the code below demonstrates most of the necessary concepts for shell communication:
public static void Main()
{
using (Process process = new Process())
{
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.WorkingDirectory = #"C:\";
process.StartInfo.FileName = Path.Combine(Environment.SystemDirectory, "cmd.exe");
// Redirects the standard input so that commands can be sent to the shell.
process.StartInfo.RedirectStandardInput = true;
// Runs the specified command and exits the shell immediately.
//process.StartInfo.Arguments = #"/c ""dir""";
process.OutputDataReceived += ProcessOutputDataHandler;
process.ErrorDataReceived += ProcessErrorDataHandler;
process.Start();
process.BeginOutputReadLine();
process.BeginErrorReadLine();
// Send a directory command and an exit command to the shell
process.StandardInput.WriteLine("dir");
process.StandardInput.WriteLine("exit");
process.WaitForExit();
}
}
public static void ProcessOutputDataHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
Console.WriteLine(outLine.Data);
}
public static void ProcessErrorDataHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
Console.WriteLine(outLine.Data);
}
You may have threading issues causing your problems. I've done some further work with this and was able to get a textbox on a form to update with the following code:
using System;
using System.Diagnostics;
using System.IO;
using System.Timers;
namespace DummyFormsApplication
{
class ProcessLauncher : IDisposable
{
private Form1 form;
private Process process;
private bool running;
public bool InteractiveMode
{
get;
private set;
}
public ProcessLauncher(Form1 form)
{
this.form = form;
process = new Process();
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.WorkingDirectory = #"C:\";
process.StartInfo.FileName = Path.Combine(Environment.SystemDirectory, "cmd.exe");
// Redirects the standard input so that commands can be sent to the shell.
process.StartInfo.RedirectStandardInput = true;
process.OutputDataReceived +=new DataReceivedEventHandler(process_OutputDataReceived);
process.ErrorDataReceived += new DataReceivedEventHandler(process_ErrorDataReceived);
process.Exited += new EventHandler(process_Exited);
}
public void Start()
{
if (running == false)
{
running = true;
InteractiveMode = true;
// Runs the specified command and exits the shell immediately upon completion.
process.StartInfo.Arguments = #"/c ""C:\python27\python.exe -i""";
process.Start();
process.BeginOutputReadLine();
process.BeginErrorReadLine();
}
}
public void Start(string scriptFileName)
{
if (running == false)
{
running = true;
InteractiveMode = false;
// Runs the specified command and exits the shell immediately upon completion.
process.StartInfo.Arguments = string.Format(#"/c ""C:\python27\python.exe ""{0}""""", scriptFileName);
}
}
public void Abort()
{
process.Kill();
}
public void SendInput(string input)
{
process.StandardInput.Write(input);
process.StandardInput.Flush();
}
private void process_OutputDataReceived(object sendingProcess, DataReceivedEventArgs outLine)
{
if (outLine.Data != null)
{
form.Invoke(form.appendConsoleTextDelegate, new object[] { outLine.Data });
}
}
private void process_ErrorDataReceived(object sendingProcess, DataReceivedEventArgs outLine)
{
if (outLine.Data != null)
{
form.Invoke(form.appendConsoleTextDelegate, new object[] { outLine.Data });
}
}
private void process_Exited(object sender, EventArgs e)
{
running = false;
}
public void Dispose()
{
if (process != null)
{
process.Dispose();
}
}
}
}
I created a form and added a textbox and the following code in the form:
public delegate void AppendConsoleText(string text);
public AppendConsoleText appendConsoleTextDelegate;
private void Form1_Load(object sender, EventArgs e)
{
appendConsoleTextDelegate = new AppendConsoleText(textBox1_AppendConsoleText);
using (ProcessLauncher launcher = new ProcessLauncher(this))
{
launcher.Start();
launcher.SendInput("import sys;\n");
launcher.SendInput("print \"Test.\";\n");
launcher.SendInput("exit()\n");
}
}
private void textBox1_AppendConsoleText(string text)
{
textBox1.AppendText(string.Format("{0}\r\n", text));
}
One thing to note is that if the Form1_Load event doesn't complete, Invoke will hang until it does. If you have long-running code in an event you'll either need to invoke asynchronously using BeginInvoke, or periodically call DoEvents in your long-running code.
EDIT
Per your comment, I've modified the code to work with interactive submissions. There is, however, a problem. The python prompt (>>>) is provided on the StandardError output and it does not echo the StandardInput. It also does not terminate the line. This makes detecting a prompt difficult and causes some out of order output of the prompt characters due to the process_ErrorDataReceived not firing until either the process ends or a line end is seen.
There's not enough code in your question to figure out exactly what your application is hanging on. There are some things in your code which look odd. For example, why are you starting your own error and output read loops instead of using the ones built into the Process class? Like this:
var shellProcess = System.Diagnostics.Process.Start(info);
shellProcess.EnableRaisingEvents = true;
shellProcess.Exited += ProcessExited;
shellProcess.OutputDataReceived += ShellProcess_OutputDataReceived;
shellProcess.ErrorDataReceived += ShellProcess_ErrorDataReceived;
shellProcess.BeginOutputReadLine();
shellProcess.BeginErrorReadLine();
void ShellProcess_ErrorDataReceived(object sender, DataReceivedEventArgs e)
{
// Do Something
}
void ShellProcess_OutputDataReceived(object sender, DataReceivedEventArgs e)
{
// Do Something
}
Since your error and output async events are not firing, it leads me to believe that there might be a lifetime issue with the shellProcess. If you post more of your code, we can give better guidance.
I can't see all your code, but you can easily use Steam objects to write/send commands to the CMD Window created by you. e.g.:
StreamWriter inputStream = shellProcess.StandardInput;
//send command to cmd prompt and wait for command to execute with thread sleep
inputStream.WriteLine("echo "CMD just received input");
inputStream.Flush();
In the above example for instance, Command prompt will receive the echo command just like it was entered in the window. To show the output you will have to create StreamReader object and assign it to the process's StandardOutput.
Related
I need to execute a Process (CMD executing a script) called from within a Windows Forms app, and update some controls when getting Output from the process.
I am using Windows Forms in .NET Core 5.0.
I have been researching a bit and found the example Extension method InvokeIfRequired,
public static void InvokeIfRequired(this Control control, MethodInvoker action)
{
if (control.InvokeRequired) control.Invoke(action);
else action();
}
Though at first I tried just using that same structure but for each control I needed to update.
This is the code of the function I am calling the process from, and trying to update the controls from:
private int StartGeneration()
{
int result = 0;
using (Process cmd = new Process())
{
cmd.StartInfo.FileName = "cmd.exe";
cmd.StartInfo.WorkingDirectory = #"C:\git\pub";
cmd.StartInfo.RedirectStandardInput = true;
cmd.StartInfo.RedirectStandardOutput = true;
cmd.StartInfo.CreateNoWindow = true;
cmd.Start();
cmd.Exited += (sender, e) =>
{
Console.WriteLine("Exiting from CMD process");
};
cmd.OutputDataReceived += (sender, e) =>
{
lbResult.InvokeIfRequired(new MethodInvoker(delegate
{
lbResult.Text = e.Data;
}));
if (e.Data.ToLower().Contains("exiting"))
{
// The script has ended
lbResult.InvokeIfRequired(new MethodInvoker(delegate
{
lbResult.ForeColor = System.Drawing.Color.Aqua;
lbResult.Text = "Done";
}));
rtbResult.InvokeIfRequired(new MethodInvoker(delegate
{
rtbResult.Visible = true;
rtbResult.Text = cmd.StandardOutput.ReadToEnd();
Size = new System.Drawing.Size(Width, Height + 460);
}));
cmd.StandardInput.Flush();
cmd.StandardInput.Close();
cmd.Close();
}
};
cmd.BeginOutputReadLine();
cmd.StandardInput.WriteLine(BuildPublishingScriptCommand());
cmd.WaitForExit();
}
return result;
}
And the BuildPublishingScriptCommand() function is just a simple function that returns a string, containing the script I need to run in the CMD.
The problem comes when the code gets in the OutputDataReceived event of the process and I try to use the InvokeIfRequired method (or any Invoke method in general).
The application just keeps running infinitely but nothing updates. Though the script completes successfully because I can confirm the work is done (creates some DLLs).
If I debug, I get until the call to InvokeIfRequired and then I lose control to debugging.
It does not give any exception.
I have not tried anything else.
I've built Form App that I use for some time , Now I want to Catch the StandardError of my process as well as its standartOutput
I've looked at answers in SO and MSDN and yet and cant get it right
My code :
public void RunProcess(string FileName, string Arguments,, bool IsPrintOutput = true)
{
process = new Process();
process.ErrorDataReceived += new DataReceivedEventHandler(OnDataReceivedEvent);
if (IsPrintOutput) process.OutputDataReceived += new DataReceivedEventHandler(OnDataReceivedEvent);
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.CreateNoWindow = true;
process.StartInfo.UseShellExecute = false;
process.StartInfo.FileName = FileName;
process.StartInfo.Arguments = Arguments;
if (EventWhenExit)
{
process.EnableRaisingEvents = true;
process.Exited += new EventHandler(myprocess_Exited);
}
process.Start();
process.BeginOutputReadLine();
//run polling on stored logs to print them to screen
PollingService();
}
I've check it with Iperf and I see that when I run it with correct argument I get correct output
but when I just send it with out any argumnet I see that with cmd I get
C:\>iperf.exe
Usage: iperf [-s|-c host] [options]
Try `iperf --help' for more information.
And my App I get Nothing !
what am I missing here ?
Thanks
You can stop reading here ! If you want to see the details of inner method continue below :
private void OnDataReceivedEvent(object sender, DataReceivedEventArgs e)
{
string ProcessOutput = e.Data;
ProcessLog.Add(e.Data);
}
private void PollingService()
{
var T = new Thread (()=>
{
while (true /* ProcessRunning*/)
{
if (ProcessLogIndex < ProcessLog.Count)
{
lock (this)
{
var tempList = ProcessLog.GetRange(ProcessLogIndex, ProcessLog.Count - ProcessLogIndex);
ProcessLogIndex = ProcessLog.Count;
foreach (var ToSend in tempList)
{
onDataOutputFromProcess(this, ToSend, sProcessNameID.ToString());
}
}
}
Thread.Sleep(400);
}
});
T.IsBackground = true;
T.Start();
}
I don't see a call to BeginErrorReadLine() anywhere in the code you posted. If you don't call that method, then the Process class won't actually redirect the stderr to your event handler.
I believe the above is the issue, but if you are actually calling that somewhere (and just didn't show it), then it is worth considering that there are some strange console programs out there that don't actually used stderr (or stdout) for error output. Instead, they write directly to the console window or some other non-standard mechanism. In those cases, you won't be able to receive the error output by redirecting stderr.
You can identify those programs by redirecting their output at the command like with e.g. iperf.exe 2> foo.txt. The stderr file handle is 2, and so that syntax redirects that file handle to a file named foo.txt. If the file is empty and you see errors on the screen, then the program is one of those strange programs.
But really, I think you probably just forgot to call BeginErrorReadLine(). :)
Similar to
Process.Start("IEXPLORE.EXE") immediately fires the Exited event after launch.. why?
The -nomerge option does not seem to work for firefox.
Updated:
Here's a preview of the C# code inside a console app
static bool exitCalled = false;
static string baseUrl = <some url to display in the browser>;
var process = new Process
{
StartInfo = new ProcessStartInfo
{
FileName = "Firefox.exe"
Arguments = " -url " + baseUrl + " -no-remote -P MyProfile "
}
}
process.EnableRaisingEvents = true;
process.Exited += new EventHandler(delegate(Object o, EventArgs e)
{
// process has exited
Console.WriteLine("Exited event called");
Console.ReadLine();
exitCalled = true;
}
process.Start();
while (!exitCalled)
{
Thread.Sleep(100);
}
Running this piece of code displays the "Exited event called" message before the browser is invoked.
That because -nomerge is an IE specific program argument, for firefox you need to use -no-remote. You will also need to pass it the -P program argument as well since it is not recommend to start another firefox process with the default profile. Refer to the following link on starting a new FireFox instance:
http://kb.mozillazine.org/Opening_a_new_instance_of_Firefox_with_another_profile
I'm trying to build a c# program that will pass string to an existing console application and will get back string after it is done processing.
Here is how I would want it to work:
public void InitializeUtil(List<object> items)
{
Process DataValidationUtilitty = new Process();
DataValidationUtilitty.StartInfo.FileName = Configuration.DVUTIL;
DataValidationUtilitty.StartInfo.CreateNoWindow = false;
DataValidationUtilitty.StartInfo.WindowStyle = ProcessWindowStyle.Maximized;
DataValidationUtilitty.StartInfo.RedirectStandardInput = true;
DataValidationUtilitty.StartInfo.RedirectStandardOutput = true;
DataValidationUtilitty.StartInfo.RedirectStandardError = true;
DataValidationUtilitty.StartInfo.UseShellExecute = false;
DataValidationUtilitty.OutputDataReceived += new DataReceivedEventHandler(InterProcOutputHandler);
DataValidationUtilitty.ErrorDataReceived += new DataReceivedEventHandler(InterProcOutputHandler);
DataValidationUtilitty.Start();
DataValidationUtilitty.BeginOutputReadLine();
DataValidationUtilitty.StandardInput.WriteLine(items[0].ToString());
}
public void InterProcOutputHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
Console.WriteLine(outLine.Data.ToString());
}
// And I call
Program ThisProgram = new Program();
ThisProgram.InitializeUtil(items);
For some obvious reasons this does not work and I don't know why.
Here is a working example:
I have here executable with DLL that it needs
I have an input string in document.json file
I have a .bat file that will run this executable
Run the program and pass document.json as input string
Pause execution to see the results
Get back correct string
What am I missing here, what don't I understand about this process? I was assured from dvutils.exe developers that program does std input,output,error.
I have a console application and in the Main method. I start a process like the code below, when process exists, the Exist event of the process is fired but it closed my console application too, I just want to start a process and then in exit event of that process start another process.
It is also wired that process output is reflecting in my main console application.
Process newCrawler = new Process();
newCrawler.StartInfo = new ProcessStartInfo();
newCrawler.StartInfo.FileName = configSection.CrawlerPath;
newCrawler.EnableRaisingEvents = true;
newCrawler.Exited += new EventHandler(newCrawler_Exited);
newCrawler.StartInfo.Arguments = "someArg";
newCrawler.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
newCrawler.StartInfo.UseShellExecute = false;
newCrawler.Start();
You have to call newCrawler.WaitForExit() in order to stay until the child process finish. Then you can use newCrawler.ExitCode to have the exit value.
Seems like the Process exit handling could have caused the application error. So the application could have terminated. Can you put a proper try..catch block and debugg to see what is going wrong. Or comment the
line
newCrawler.Exited += new EventHandler(newCrawler_Exited);
and see what happens.
Please try following code (This is from MSDN) , also don't forget to pass one argument (FileName)
using System;
using System.Diagnostics;
using System.ComponentModel;
using System.Threading;
using Microsoft.VisualBasic;
class PrintProcessClass
{
private Process myProcess = new Process();
private int elapsedTime;
private bool eventHandled;
// Print a file with any known extension.
public void PrintDoc(string fileName)
{
elapsedTime = 0;
eventHandled = false;
try
{
// Start a process to print a file and raise an event when done.
myProcess.StartInfo.FileName = fileName;
myProcess.StartInfo.Verb = "Print";
myProcess.StartInfo.CreateNoWindow = true;
myProcess.EnableRaisingEvents = true;
myProcess.Exited += new EventHandler(myProcess_Exited);
myProcess.Start();
}
catch (Exception ex)
{
Console.WriteLine("An error occurred trying to print \"{0}\":" + "\n" + ex.Message, fileName);
return;
}
// Wait for Exited event, but not more than 30 seconds.
const int SLEEP_AMOUNT = 100;
while (!eventHandled)
{
elapsedTime += SLEEP_AMOUNT;
if (elapsedTime > 30000)
{
break;
}
Thread.Sleep(SLEEP_AMOUNT);
}
}
// Handle Exited event and display process information.
private void myProcess_Exited(object sender, System.EventArgs e)
{
eventHandled = true;
Console.WriteLine("Exit time: {0}\r\n" +
"Exit code: {1}\r\nElapsed time: {2}", myProcess.ExitTime, myProcess.ExitCode, elapsedTime);
}
public static void Main(string[] args)
{
// Verify that an argument has been entered.
if (args.Length <= 0)
{
Console.WriteLine("Enter a file name.");
return;
}
// Create the process and print the document.
PrintProcessClass myPrintProcess = new PrintProcessClass();
myPrintProcess.PrintDoc(args[0]);
}
}
One thing I noticed is, if you are not passing the filename as parameter, that will lead the process to crash, but still the application is intact (Since the exception is handled inside the process).
If you are not passing the filename the above code will crash beacuse the
myPrintProcess.PrintDoc(args[0]);
will throw exception from main process itself.
I tried to create an exceptin inside the Exit handler, at that time the application (main process) also crashed.
can you try commenting the code inside Exit handler?