Calling a C# library from python

Question

Anyone can share a working example on how to call a simple C# library (actually its WPF) from python code? (I have tried using IronPython and had too much trouble with unsupported CPython library my python code is using so I thought of trying the other way around and calling my C# code from Python).

Here is the example I was playing with:

using System.Runtime.InteropServices;
using System.EnterpriseServices;

namespace DataViewerLibrary
{
    public interface ISimpleProvider
    {
       [DispIdAttribute(0)]
       void Start();
    }

    [ComVisible(true)]
    [ClassInterface(ClassInterfaceType.None)]
    public class PlotData : ServicedComponent, ISimpleProvider
    {
       public void Start()
       {
          Plot plotter = new Plot();
          plotter.ShowDialog();
       }
    }
}

Plotter is a WPF windows that plots an Ellipse

I don't know how to call this code from my python all. Any suggestions?

Answer 1

It is actually pretty easy. Just use NuGet to add the "UnmanagedExports" package to your .Net project. See https://sites.google.com/site/robertgiesecke/Home/uploads/unmanagedexports for details.

You can then export directly, without having to do a COM layer. Here is the sample C# code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using RGiesecke.DllExport;

class Test
{
    [DllExport("add", CallingConvention = CallingConvention.Cdecl)]
    public static int TestExport(int left, int right)
    {
        return left + right;
    }
}

You can then load the dll and call the exposed methods in Python (works for 2.7)

import ctypes
a = ctypes.cdll.LoadLibrary(source)
a.add(3, 5)