如何将C＃dll导入python

Question

i've got a third party c# dll which has been created in dot net 4.5 and has a platform target of x86. I would like to import this into a python script and I've started off with Rob Deary's answer here . However I can't get his example to work. I'm using python version 2.7.6 and I get an AttributeError as shown below.

File "C:\Python27\Lib\ctypes\__init__.py", line 378, in __getattr__
    func = self.__getitem__(name)
File "C:\Python27\Lib\ctypes\__init__.py", line 383, in __getitem__
    func = self._FuncPtr((name_or_ordinal, self))
AttributeError: function 'add' not found

Please note that I am aware of Ironpython and Python for dot net but I need to get this working specifically with C python. Here's my sample code which generates the custom c# library: ClassLibrary1.dll

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

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

And here's the python script that generates the error

import ctypes
lib = ctypes.cdll.LoadLibrary('ClassLibrary1.dll')
lib.add(3,5)

When I use the line below, this is the output i get. So at least I know that it is loading the dll, but i'm not sure why the function can't be found.

>>> lib.__dict__
{'_FuncPtr': <class 'ctypes._FuncPtr'>, '_handle': 254476288, '_name': 'ClassLibrary1.dll'}
>>>

Any help will be appreciated. Thanks

Answer 1

As the RGiesecke.DllExport documentation states, you need to target a specific architecture (x86 or x64) when building your code. Leaving it set to Any CPU (the default) will not work.