How to Run a Python Script from C#

How do I run a Python script from C#?

The reason it isn't working is because you have UseShellExecute = false.

If you don't use the shell, you will have to supply the complete path to the python executable as FileName, and build the Arguments string to supply both your script and the file you want to read.

Also note, that you can't RedirectStandardOutput unless UseShellExecute = false.

I'm not quite sure how the argument string should be formatted for python, but you will need something like this:

private void run_cmd(string cmd, string args)
{
     ProcessStartInfo start = new ProcessStartInfo();
     start.FileName = "my/full/path/to/python.exe";
     start.Arguments = string.Format("{0} {1}", cmd, args);
     start.UseShellExecute = false;
     start.RedirectStandardOutput = true;
     using(Process process = Process.Start(start))
     {
         using(StreamReader reader = process.StandardOutput)
         {
             string result = reader.ReadToEnd();
             Console.Write(result);
         }
     }
}

calling python.py from C# .net

The following code snippet worked for me : C# code to call Python

using System;
using System.Diagnostics;
using System.IO;
namespace ScriptInterface
{
    public class ScriptRunner
    {
        //args separated by spaces
        public static string RunFromCmd(string rCodeFilePath, string args)
        {
            string file = rCodeFilePath;
            string result = string.Empty;

            try
            {

                var info = new ProcessStartInfo(@"C:\Users\xyz\AppData\Local\Programs\Python\Python37\python.exe");
                info.Arguments = rCodeFilePath + " " + args;

                info.RedirectStandardInput = false;
                info.RedirectStandardOutput = true;
                info.UseShellExecute = false;
                info.CreateNoWindow = true;

                using (var proc = new Process())
                {
                    proc.StartInfo = info;
                    proc.Start();
                    proc.WaitForExit();
                    if (proc.ExitCode == 0)
                    {
                        result = proc.StandardOutput.ReadToEnd();
                    }                    
                }
                return result;
            }
            catch (Exception ex)
            {
                throw new Exception("R Script failed: " + result, ex);
            }
        }
        public static void Main()
        {
            string args = "1 2";
            string res = ScriptRunner.RunFromCmd(@"your file path", args);

        }
    }

}

and following Python Code which takes two inputs and returns the sum of those:

import sys
def add_numbers(x,y):
   sum = x + y
   return sum

num1 = int(sys.argv[1])
num2 = int(sys.argv[2])

print(add_numbers(num1, num2))

Executing Python Script from Windows Forms .NET

After some struggle, I found a solution to fit my needs.

Firstly, I completely removed python 2.7 and installed back 3.10.

I tried running the script file inside the shell command line and got the same error that the modules could not be found. What I did is try to import these modules and it gave an error, specifically for bs4 that I am using packages for python 2.x instead of 3.x packages.

After futher investigation I discovered that the packages that I have for my script are treated as "local" packages, meaning I installed them from the IDE (PyCharm) and they work for that project only I guess.

I also found that to "globally" access these packages I had to install them through the command line using the pip3 install <package_name>. After doing this the problem was gone and was left with running the script from the Windows Forms.

NOTE: I did not manage to start the script using python.exe, so I used bash script for the job.

Here is my code and I hope it helps someone down the line...

Code in C#

string myApp = string.Format("{0} {1}", @"C:\testing1.sh", "Hello");

var processStartInfo = new ProcessStartInfo
{
  Arguments = myApp,
  FileName = "C:\\Program Files\\Git\\git-bash.exe",
  UseShellExecute = false,
  RedirectStandardOutput = true,
  CreateNoWindow = false
};

Process.Start(processStartInfo)

Code in Bash Script File

#!/bin/bash

arg1="$1"

python C:/Users/Dobromir/PycharmProjects/testing/main.py "$arg1"

Inside the Python file I am using sys.argv[] and accessing the arguments.

NOTE: Passing arguments from the bash script to the python script, in this case, you will receive 2 arguments - first one is the path to the python file and the second is the variable arg1.

Another important thing to mention is you need to have comas around the $1 - this is the property that is being send from the C# file, else it will show as empty.

Articles that were useful:

Installed BeautifulSoup but still get no module named bs4

Passing arguments to Python from Shell Script

https://unix.stackexchange.com/questions/31414/how-can-i-pass-a-command-line-argument-into-a-shell-script

https://gist.github.com/creativcoder/6df4d349447ff1416e68

Thank you to everyone who contributed and tried to help, I managed to learned new things with your suggestions!

Python.Net - How to run python script from file(.Py)

Finally i ended up with the following solution.

using (Py.GIL()){
    dynamic os = Py.Import("os");
    dynamic sys = Py.Import("sys");
    sys.path.append(os.path.dirname(os.path.expanduser(filePath)));
    var fromFile = Py.Import(Path.GetFileNameWithoutExtension(filePath));
    fromFile.InvokeMethod("replace");
}

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