Run python script from C# via command prompt

I’m developing a Winform application. I want to run python script from c# via command prompt (i’m using System.Diagnostics.Process class) I have a function to run python script that need to pass a python script file name.

        public void Run(string cmd)
        {
            Process p = new Process()
            {
                StartInfo = new ProcessStartInfo()
                {
                    FileName = "python",
                    CreateNoWindow = true,
                    UseShellExecute = false,
                    ErrorDialog = false,
                    RedirectStandardInput = true,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true,
                    WorkingDirectory = Directory.GetCurrentDirectory() + @"PythonScripts",
                    Arguments = string.Format("{0}", cmd)
                },
                EnableRaisingEvents = true,
                SynchronizingObject = this
            };
            p.OutputDataReceived += (s, e) => SetOutputText(e.Data);
            p.ErrorDataReceived += (s, e) => SetErrorText(e.Data);
            p.Start();
            p.BeginOutputReadLine();
            p.BeginErrorReadLine();
        }

It works correctly until I print a string that contain unicode character. My test.py code contains just a single line.

print("xin chào việt nam")

When I compiled this test.py command prompt from start it worked perfectly. But when I compiled from c# via command prompt I got this error:

Traceback (most recent call last):  
File "test.py", line 1, in <module>    ufeffprint("xin chào viu1ec7t nam")  
File "C:UsersD SeriousAppDataLocalProgramsPythonPython36libencodingscp1252.py", line 19, in encode    
return codecs.charmap_encode(input,self.errors,encoding_table)
[0]UnicodeEncodeError: 'charmap' codec can't encode character 'u1ec7' in position 11: character maps to <undefined>

I think the problem here caused by C# when it run command prompt and read the python script, the process can not decode utf8 correctly. Thank you.

Answer

After hours finding the reason, I found it. Python decoding doesn’t have problem, that is command prompt problem. So that I fix my function to:

public void Run(string cmd)
{
    Process p = new Process()
    {
        StartInfo = new ProcessStartInfo()
        {
            FileName = "cmd",
            CreateNoWindow = true,
            UseShellExecute = false,
            ErrorDialog = false,
            RedirectStandardInput = true,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            WorkingDirectory = Directory.GetCurrentDirectory() + @"PythonScripts",
            StandardOutputEncoding = Encoding.UTF8,
            StandardErrorEncoding = Encoding.UTF8,
            StandardInputEncoding = Encoding.UTF8
        },
        EnableRaisingEvents = true,
        SynchronizingObject = this
    };
    p.Start();
    using (StreamWriter sw = p.StandardInput)
    {
        sw.WriteLine("chcp 65001");
        sw.WriteLine("set PYTHONIOENCODING=utf-8");
        sw.WriteLine($"python {cmd}");
    }
    p.OutputDataReceived += (s, e) => SetOutputText(e.Data);
    p.ErrorDataReceived += (s, e) => SetErrorText(e.Data);

    p.WaitForExit();
    p.BeginOutputReadLine();
    p.BeginErrorReadLine();
}

I added sw.WriteLine("chcp 65001"); and sw.WriteLine("set PYTHONIOENCODING=utf-8"); to get better decode unicode. Thank for your attention