Develop Reference

calling devcon from inside windows forms not working

Plan
The plan is to disable and subsequently enable a device from inside a windows forms application. To test the first building block of my plan, I open cmd with admin privileges and the following works perfectly:
> devcon hwids =ports
> devcon hwids *VID_10C4*
> devcon disable *VID_10C4*
> devcon enable *VID_10C4*
I can see the device being disabled and enabled again in device manager.
I can also achieve all of this by putting the commands into a batch file and running it from cmd with admin privileges. The above tells me that my plan is essentially good.
Application
However, what I actually want to do is achieve the same thing from inside a windows forms application:
I've set the following in the app manifest:
requestedExecutionLevel level="requireAdministrator" uiAccess="false"
For the sake of baby steps, I have checked this, just to ensure that there are no stupid mistakes in paths and whatnot. And it works just fine. The log file shows me the expected output from the dir command.
// Build String
string strCmdText =
"'/c cd " + prodPath +
" && dir " +
" > logs\\logFileEnablePrt.txt \"'";
// Run command
var p = new System.Diagnostics.Process();
var psi = new ProcessStartInfo("CMD.exe", strCmdText);
psi.Verb = "runas"; // admin rights
p.StartInfo = psi;
p.Start();
p.WaitForExit();
However, this does not work. It always returns an empty log file and does not change the device as expected:
// Build String
string strCmdText =
"'/c cd " + prodPath +
" && devcon hwids =ports " +
" > logs\\logFileEnablePrt.txt \"'";
// Run command
var p = new System.Diagnostics.Process();
var psi = new ProcessStartInfo("CMD.exe", strCmdText);
psi.Verb = "runas"; // admin rights
p.StartInfo = psi;
p.Start();
p.WaitForExit();
Error from cmd window is :
'devcon' is not recognized as an internal or external command,
operable program or batch file.
What's going on?
The above has me stumped. I've proved the commands work. I've proved my C# code works. But when I join the 2 together, it doesn't work...
NB: My C# program is running on my D: drive, if that makes any difference...
Updates Based on Comments
#Compo
Using your code, it does exactly the same as with mine. I see an empty log file & no changes made to the device. I've altered the /c to /k so I can see what going on the cmd terminal and I see this:
I've even tried your code C:\\Windows\\System32\\devcon hwids =usb pointing directly at devcon. Also tried \devcon.exe for completeness. The inexplicable error is :
I can see the flipping devcon.exe file sitting right there in the folder! Is there any reason it would not recognise it?
Also, with the command as you wrote it, the log file name is actually named logFileEnablePrt.txt'. I agree that your command looks right, so don't ask me why this happens!
#Panagiotis Kanavos
using your code, I get the following error:
This is at the line p.Start();. I tried putting in devcon.exe, and even the whole path (I checked the folder was in my PATH, and it is). Can't get past this. I actually stumbled on that answer you shared and arrived at this brick wall already.

Here is the code works for me, I don't have ports devices so I change it to usb.
public static void Main()
{
string prodPath = #"c:\devcon\x64";
// Build String
string strCmdText =
"/c \"cd /d " + prodPath +
" && devcon hwids =usb " +
" > log.txt \"";
// Run command
var p = new Process();
var psi = new ProcessStartInfo("CMD.exe", strCmdText);
psi.Verb = "runas"; // admin rights
p.StartInfo = psi;
p.Start();
p.WaitForExit();
}

Worked through a few steps and think I may have an answer...
Just specifying devcon fails as expected...windows cant find the exe as the folder it is in is not in the %PATH% variable in windows..
IF I specify the full path however it works...
It wasnt clear from your original code but if your copy of devcon is sitting in either System32 or Syswow directories you may be hitting an emulation issue as well...see here....
EDIT1:: A way to prove this would be to do Direcory.GetFiles(directory containing devcon) and see if the results line up with what you expect
As for passing arguments through to devcon I'd try something like this as opposed to trying to concatenate one giant cmd line..
A similar example but with netstat:
EDIT 2::Another example but with devcon:
The target platform here for the build was x64
EDIT3::
With my application build set to x86:

After working through the answers and comments above, I seem to have something that reliably works, which obviously I'd like to share back for scrutiny and future use.
So, my function ended up looking like this:
private int enablePort(string action)
{
while (true)
{
// Command Arg
string devconPath = #"c:\Windows\SysNative";
string strCmdText =
"'/c \"cd /d \"" +
devconPath +
"\" && c:\\Windows\\SysNative\\devcon " + action + " *VID_10C4* " +
"> \"" + prodPath + "\\logs\\logFileEnablePrt.txt\"\"";
// Process
var p = new Process();
var psi = new ProcessStartInfo()
{
Arguments = strCmdText,
Verb = "runas",
FileName = "CMD.exe",
UseShellExecute = true
};
p.StartInfo = psi;
p.Start();
p.WaitForExit();
// Grab log output
string logPath = prodPath + "\\logs\\logFileEnablePrt.txt";
Console.WriteLine("logPath = " + logPath);
string tempFile = System.IO.File.ReadAllText(logPath);
System.Console.WriteLine("Contents of WriteText.txt = \n{0}", tempFile);
// Check if it worked
var success = false;
if (tempFile.Contains(action))
{
success = true;
return 0;
}
// Error -> Allow user to try again!
if (MessageBox.Show("Was unable to " + action + " Test Jig COM port. Unlug & Replug USB. Check COM port is enabled if not working.", "COM Port Problem", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.No)
{
return -1;
}
}
}
And the calling code was:
this.enablePort("disable");
int milliseconds = 3000;
await Task.Delay(milliseconds);
this.enablePort("enable");
As you can see in the code above, I've logged everything to see what was going on... Stepping through with the debugger, I can now see after the disable:
USB\VID_10C4&PID_EA60\0001 : Disabled
1 device(s) disabled.
And then after the enable:
USB\VID_10C4&PID_EA60\0001 : Enabled
1 device(s) are enabled.
The one extra thing I need to stress is that during testing, I thought I could hook a serial peripheral onto the port and determine whether it could disable and enable successfully by checking the connection. THIS DOES NOT WORK. The above code only works when the port is idle. Perhaps someone who understands the underlying software could hazard an explanation of why this is.

Start app remotely on computer in c#

I want to start an app remotely from my PC on another pc with c# code. I want to have one c# code and on another computer that the app is there and I want to run app on it, don't want to put a c# code. How can I do it?!

ProcessStartInfo info = new ProcessStartInfo("C:\\PsTools");
info.FileName = #"C:\PsTools\psexec.exe";
info.Arguments = #"\\" + serverName + #" -i C:\WINDOWS\notepad.exe";
info.RedirectStandardOutput = true;
info.UseShellExecute = false;
Process p = Process.Start(info);

Calling GhostScript with Process() in C# Web API Web Service

I am trying to print a pdf file from a WebAPI Web Service by calling GhostScript using Process()
This works perfectly when 'Debugging' an ASP.NET application on my local machine, but when I use the exact same code to try and print through a Web Service - also on my local machine - it doesn't work.
I don't get any kind of exception in VS - so far as the application is concerned, the application is working fine.
Here's the code I'm using to call the GhostScript printer:
Process process = new Process();
process.StartInfo.Arguments = #" -dPrinted -dBATCH -dNOPROMPT -dNOPAUSE -dNOSAFER -q -dNumCopies=1 -sDEVICE=mswinpr2 -dNoCancel -sPAPERSIZE=a4 -sOutputFile=\\spool\\\printserver\printer c:\\test\test.pdf";
process.StartInfo.FileName = #"C:\Program Files (x86)\GPLGS\gswin32c.exe";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.RedirectStandardOutput = true;
StringBuilder output = new StringBuilder();
StringBuilder error = new StringBuilder();
using (AutoResetEvent outputWaitHandle = new AutoResetEvent(false))
using (AutoResetEvent errorWaitHandle = new AutoResetEvent(false))
{
process.OutputDataReceived += (sender, e) => {
if (e.Data == null)
{
outputWaitHandle.Set();
}
else
{
Console.Write(e.Data);
output.AppendLine(e.Data);
}
};
process.ErrorDataReceived += (sender, e) =>
{
if (e.Data == null)
{
errorWaitHandle.Set();
}
else
{
Console.Write(e.Data);
error.AppendLine(e.Data);
}
};
process.Start();
process.BeginOutputReadLine();
process.BeginErrorReadLine();
process.WaitForExit();
if (process.HasExited == false) process.Kill();
return process.ExitCode == 0;
I thought this might have something to do with printers not being installed for All Users so have added them for all users. The only other thing that I can see it being is Permissions - but can't figure out a solution.
Does anyone have any ideas?
Thanks in advance for your help. :)

As suspected, this turned out to be a Permissions issue. After publishing the Web Service to IIS, I changed the Default Application Pool to use a User Identity, the printing suddenly started working correctly.
I will set up a user account specifically for printing - with no write permissions - and use this for now.

System.Diagnostics.Process can't start process

I'm creating a service on VS2010, using .net framework 4.0 Client Profile. The target machine is Windows Server 2003 64 bits. This service move some files and then executes a process with System.Diagnostics.Process. The trouble is that, even if the taskmanager shows a process as starting, the executable never do whats was made for. Example code:
private void imprimir(string nombreImpresora, int copias, string nombreArchivo)
{
try
{
string copiasSumatra = "1,";
for (int i = 1; i < copias; i++)
{
copiasSumatra += "1,";
}
string path = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
string comando = String.Format("-print-to \"{0}\" \"{1}\" -print-settings \"{2}odd,fit\" -silent", nombreImpresora, nombreArchivo, copiasSumatra);
string filename = '"' + Path.Combine(path, "SumatraPDF.exe") + '"';
System.Diagnostics.Process proc = new System.Diagnostics.Process();
proc.StartInfo.WorkingDirectory = path;
proc.StartInfo.FileName = filename;
proc.StartInfo.Arguments = comando;
proc.StartInfo.RedirectStandardError = false;
proc.StartInfo.RedirectStandardOutput = false;
proc.StartInfo.UseShellExecute = true;
proc.StartInfo.ErrorDialog = false;
proc.Start();
proc.WaitForExit();
lc.writeToLog("Instruction executed. Exit code: " + proc.ExitCode);
}
catch (Exception ex)
{
lc.writeToLog(ex.Message + " " + ex.StackTrace);
}
}
If I execute it on my dev machine (windows 8 pro) or in another test server (Windows Server 2003 32 bits) it makes whats expected. If I run it on the WS2003 64 bit server it does nothing.
I've debugged lots of times to see if it produces some error that I'm missing, but nothing happens. The "lc.writeToLog" method prints text to a file. I've used it to log every single line of the execution, but no error is thrown. Using that method I've concluded that it passes the "proc.WaitForExit()" instruction, so I think it's going to do what I've programmed, but nothing happens.
I have runned the same instruction but passing it a user, password and domain and the result was the same. Also tryed to capture standard error and output but it contained nothing.
What could be the trouble?

It was a server related issue. After deploying the application onto the production server the issue has disapeared.

Could not find a part of the path :While copying file on Mapped drive using Windows Service

I have a Windows Service which goes and update some files on the Network which is mapped as drive "Z:\". When i run the code from VS as administrator I am able to copy the file on the mapped drive but same thing fails when it is run from the Service which is running under administrator account.
The Mapped drive is created from same account under which service is running. Bit puzzling why its working when run from the VS but not from service.
Is it better to use UNC than network drive.
There is a workaround at below forum
http://support.microsoft.com/default.aspx?scid=kb;en-us;827421#appliesto
but it has used UNC not mapped drive.

We experienced this as well, and while I can't tell you WHY our resolution worked, i can tell you WHAT worked.
Map the drive in the code. Don't rely on the drive being mapped just because you're using the same account.
Based on the behavior we saw, this is what i would GUESS was happening in our situation and what's happening in yours.
The service we had issues with used a drive that was mapped in a login script. If we had the machine logged in as the same user the service was using, it worked, but if not it wouldn't work. Based on that, I surmised that the drive simply isn't mapped because the service doesn't really "log on".
Mapping the drive in code fixed it.
As a side note, you can also reference the UNC path directly, but we had permissions issues with that as well. Mapping the drive, passing in a username and password worked much better for us.
Our code for doing this:
public static class NetworkDrives
{
public static bool MapDrive(string DriveLetter, string Path, string Username, string Password)
{
bool ReturnValue = false;
if(System.IO.Directory.Exists(DriveLetter + ":\\"))
{
DisconnectDrive(DriveLetter);
}
System.Diagnostics.Process p = new System.Diagnostics.Process();
p.StartInfo.UseShellExecute = false;
p.StartInfo.CreateNoWindow = true;
p.StartInfo.RedirectStandardError = true;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.FileName = "net.exe";
p.StartInfo.Arguments = " use " + DriveLetter + ": " + '"' + Path + '"' + " " + Password + " /user:" + Username;
p.Start();
p.WaitForExit();
string ErrorMessage = p.StandardError.ReadToEnd();
string OuputMessage = p.StandardOutput.ReadToEnd();
if (ErrorMessage.Length > 0)
{
throw new Exception("Error:" + ErrorMessage);
}
else
{
ReturnValue = true;
}
return ReturnValue;
}
public static bool DisconnectDrive(string DriveLetter)
{
bool ReturnValue = false;
System.Diagnostics.Process p = new System.Diagnostics.Process();
p.StartInfo.UseShellExecute = false;
p.StartInfo.CreateNoWindow = true;
p.StartInfo.RedirectStandardError = true;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.FileName = "net.exe";
p.StartInfo.Arguments = " use " + DriveLetter + ": /DELETE";
p.Start();
p.WaitForExit();
string ErrorMessage = p.StandardError.ReadToEnd();
string OuputMessage = p.StandardOutput.ReadToEnd();
if (ErrorMessage.Length > 0)
{
throw new Exception("Error:" + ErrorMessage);
}
else
{
ReturnValue = true;
}
return ReturnValue;
}
}
Using the above class, you can map and disconnect the drive at will. If this is a service, I would recommend mapping the drive just before you need it and disconnecting the drive immediately after you need it.

I would suggest UNC is a better idea.
What if the mapped drive is mapped on login? A service may run without a user even logging in so the mapping might never be created.

I struggled a lot (~3 days) to solve the same issue. Seems it is more related to NTFS and file level permissions. It is better if you use shared location rather than a drive.