C# .NET windows form example with python calls

See original GitHub issue

I would like to ask that would it be possible to have an example .NET winform application which imports some python module, (ie numpy) and makes some call from it? I could not realy find such anywhere, and my trial fails right at the begining with

An unhandled exception of type ‘System.ArgumentNullException’ occurred in mscorlib.dll

Additional information: Value cannot be null.

Here is my code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Python.Runtime;

public partial class frmMain : Form
{
    public frmMain()
    {
        InitializeComponent();

        PythonEngine.Initialize(); //<- Error occurs here.
    }
}

Error details: error

Issue Analytics

State:
Created 7 years ago
Comments:10 (4 by maintainers)

Top GitHub Comments

1reaction

denfromufacommented, Feb 1, 2017

Have you really looked at this?

https://github.com/pythonnet/pythonnet/wiki/Troubleshooting-on-Windows-and-Linux

On Wed, Feb 1, 2017, 8:39 AM tarpista notifications@github.com wrote:

Closed #318 https://github.com/pythonnet/pythonnet/issues/318.

— You are receiving this because you commented.

Reply to this email directly, view it on GitHub https://github.com/pythonnet/pythonnet/issues/318#event-944838170, or mute the thread https://github.com/notifications/unsubscribe-auth/AHgZ5dCuN6BkxdgErOP4R6kj0G78CtTwks5rYJk5gaJpZM4Ld0Tc .

1reaction

tarpistacommented, Jan 12, 2017

Yes, I checked troubleshooting wiki, but could not succeed with it. Finally I found a workaround by using pythonnet in the other direction (as almost everyone does.), ie making .NET calls from python.

Basically now I make my gui in .NET (C#), and import it in python. In example my C# code looks like this:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Threading;

namespace NeuralNetsGUI
{
    public partial class frmMain : Form
    {
        public Action fp_btn_LoadData_Click;

        public frmMain()
        {
            InitializeComponent();
        }

        private void btn_LoadData_Click(object sender, EventArgs e)
        {
            if (fp_btn_LoadData_Click != null)
            {
                new Thread(new ThreadStart(fp_btn_LoadData_Click)).Start(); //Asynchronus call
                //fp_btn_LoadData_Click.DynamicInvoke(); //Synchronous call
            }
        }
    }
}

As a post-build event in Visual Studio, I copy the compiled NeuralNetsGUI.exe file into my python directory, so it is possible to import it in python:

import clr
clr.AddReference("System.Windows.Forms")
clr.AddReference("NeuralNetsGUI") 

import System.Windows.Forms as WinForms
import NeuralNetsGUI as NetsGUI
from System import Action


class clsNetsGUI():
    """A class that creates windows form by importing NetsGUI.frmMain()"""

    def __init__(self):
        self.MainForm = NetsGUI.frmMain()
        self.MainForm.fp_btn_LoadData_Click = (Action(self.btn_LoadData_Click)) # <-- this is where I set the event handler function 

        app = WinForms.Application
        app.Run(self.MainForm)

    def btn_LoadData_Click(self):
        """Button click event handler"""
        print("Button clicked!")

def main():
    netsgui = clsNetsGUI()


if __name__ == '__main__':
    main()