CODEWITHSUNDEEP
c#pythonpython-2.7python.net
Rahul Virpara
Rahul Virpara

Reputation: 1209

How to delegate all method calls to C# DLL in Python

I want to delegate all method call to C# DLL that we have written. I am using pythonnet to load the DLL file and call the methods from the DLL.

This is my python class and it works fine,

import clr
clr.AddReference('MyDll')
from MyDll import MyLibrary


class MyProxy:
    def __init__(self):
        self.lib = MyLibrary()

    def method1(self, first_arg, *args):
        self.lib.method1(first_arg, args)

    def method2(self, first_arg, *args):
        self.lib.method2(first_arg, args)

But I am not doing anything in python code except making a call to dll methods, so I don't want to write wrapper methods for all the methods in dll.

The above approach allows me to call python methods like, MyProxy().method1(first_arg, arg2, arg3, arg4), which in turns passes the first_arg as the first argument and arg2, arg3, arg4 as an array in the second argument to self.lib.method1(first_arg, args).

This behavior is necessary for me because all of my C# methods have signature method1(String first_arg, String[] other_args)

How can I achieve this by only implementing __getattr__ in my python class?

I have tried the below approach, but it throws error "No matching methods found",

class MyProxy:
    def __init__(self):
        self.lib = MyLibrary()

    def __getattr__(self, item):
        return getattr(self.lib, item)

Edit: I think, when I wrap a DLL method like this,

def method1(self, first_arg, *args):
    self.lib.method1(first_arg, args)

python takes care of converting other arguments except the first one to an array and pass that array to DLL method. It matches the signature of DLL method(method1(String first_arg, String[] other_args)), since python passes the second argument as an array.

Can we do anything in __getattr__ method to do the array conversion of other arguments except first one and pass on to DLL methods ?

Upvotes: 4

Views: 557

Answers (1)

Matthew Strawbridge
Matthew Strawbridge

Reputation: 20640

Not tested, but something like this might work:

class MyProxy:
    def __init__(self):
        self.lib = MyLibrary()

    def __getattr__(self, item):
        lib_method = getattr(self.lib, item)
        def _wrapper(first_arg, *args):
            return lib_method(first_arg, args)
        return _wrapper

Upvotes: 1

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