How do I execute a command-line program from C# and get back the STD OUT results. Specifically, I want to execute DIFF on two files that are programmatically selected and write the results to a text box. Yes, I could figure this out for myself, but surely someone else has done something like it and I'm lazy...
Source: Tips4all
// Start the child process.
ReplyDeleteProcess p = new Process();
// Redirect the output stream of the child process.
p.StartInfo.UseShellExecute = false;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.FileName = "YOURBATCHFILE.bat";
p.Start();
// Do not wait for the child process to exit before
// reading to the end of its redirected stream.
// p.WaitForExit();
// Read the output stream first and then wait.
string output = p.StandardOutput.ReadToEnd();
p.WaitForExit();
Code is from MSDN.
Here's a quick sample:
ReplyDelete//Create process
System.Diagnostics.Process pProcess = new System.Diagnostics.Process();
//strCommand is path and file name of command to run
pProcess.StartInfo.FileName = strCommand;
//strCommandParameters are parameters to pass to program
pProcess.StartInfo.Arguments = strCommandParameters;
pProcess.StartInfo.UseShellExecute = false;
//Set output of program to be written to process output stream
pProcess.StartInfo.RedirectStandardOutput = true;
//Optional
pProcess.StartInfo.WorkingDirectory = strWorkingDirectory;
//Start the process
pProcess.Start();
//Get program output
string strOutput = pProcess.StandardOutput.ReadToEnd();
//Wait for process to finish
pProcess.WaitForExit();
There one other parameter I found useful, which I use to eliminate the process window
ReplyDeletepProcess.StartInfo.CreateNoWindow = true;
this helps to hide the black console window from user completely, if that is what you desire.
System.Diagnostics.ProcessStartInfo psi =
ReplyDeletenew System.Diagnostics.ProcessStartInfo(@"program_to_call.exe");
psi.RedirectStandardOutput = true;
psi.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
psi.UseShellExecute = false;
System.Diagnostics.Process proc System.Diagnostics.Process.Start(psi);;
System.IO.StreamReader myOutput = proc.StandardOutput;
proc.WaitForExit(2000);
if (proc.HasExited)
{
string output = myOutput.ReadToEnd();
}
You can launch any command line program using the Process class, and set the StandardOutput property of the Process instance with a stream reader you create (either based on a string or a memory location). After the process completes, you can then do whatever diff you need to on that stream.
ReplyDeleteYou will need to use ProcessStartInfo with RedirectStandardOutput enabled - then you can read the output stream. You might find it easier to use ">" to redirect the output to a file (via the OS), and then simply read the file.
ReplyDelete[edit: like what Ray did: +1]
// usage
ReplyDeleteconst string ToolFileName = "example.exe";
string output = RunExternalExe(ToolFileName);
public string RunExternalExe(string filename, string arguments = null)
{
var process = new Process();
process.StartInfo.FileName = filename;
if (!string.IsNullOrEmpty(arguments))
{
process.StartInfo.Arguments = arguments;
}
process.StartInfo.CreateNoWindow = true;
process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.RedirectStandardOutput = true;
var stdOutput = new StringBuilder();
process.OutputDataReceived += (sender, args) => stdOutput.Append(args.Data);
string stdError = null;
try
{
process.Start();
process.BeginOutputReadLine();
stdError = process.StandardError.ReadToEnd();
process.WaitForExit();
}
catch (Exception e)
{
throw new Exception("OS error while executing " + Format(filename, arguments)+ ": " + e.Message, e);
}
if (process.ExitCode == 0)
{
return stdOutput.ToString();
}
else
{
var message = new StringBuilder();
if (!string.IsNullOrEmpty(stdError))
{
message.AppendLine(stdError);
}
if (stdOutput.Length != 0)
{
message.AppendLine("Std output:");
message.AppendLine(stdOutput.ToString());
}
throw new Exception(Format(filename, arguments) + " finished with exit code = " + process.ExitCode + ": " + message);
}
}
private string Format(string filename, string arguments)
{
return "'" + filename +
((string.IsNullOrEmpty(arguments)) ? string.Empty : " " + arguments) +
"'";
}
This may not be the best/easiest way, but may be an option:
ReplyDeleteWhen you execute from your code, add " > output.txt" and then read in the output.txt file.
There is a ProcessHelper Class in PublicDomain open source code which might interest you.
ReplyDelete