Python import dll

Question

How would I import a winDLL into python and be able to use all of its functions? It only needs doubles and strings.

Answer 1

I'm posting my experience. First of all despite all the hard work that take me to put all pieces together, importing a C# dll is easy. The way I did it is:

1) Install this nuget package (i'm not owner, is just very useful) in order to build a unmanaged dll: https://sites.google.com/site/robertgiesecke/Home/uploads/unmanagedexports

2) Your C# dll code is like this:

using System;
using RGiesecke.DllExport;
using System.Runtime.InteropServices;

public class MyClassName
{
   [DllExport("MyFunctionName",CallingConvention = CallingConvention.Cdecl)]
   [return: MarshalAs(UnmanagedType.LPWStr)]
   public static string MyFunctionName([MarshalAs(UnmanagedType.LPWStr)] string iString)
   {
       return "hello world i'm " + iString
   }
}

3) Your python code is like this:

import ctypes
#Here you load the dll into python 
MyDllObject = ctypes.cdll.LoadLibrary("C:\\My\\Path\\To\\MyDLL.dll")
#it's important to assing the function to an object
MyFunctionObject = MyDllObject.MyFunctionName
#define the types that your C# function return
MyFunctionObject.restype = ctypes.c_wchar_p
#define the types that your C# function will use as arguments
MyFunctionObject.argtypes = [ctypes.c_wchar_p]
#That's it now you can test it
print(MyFunctionObject("Python Message"))