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Using .net API with python packages

I am interested to control a number of instruments which has an API written in C# .NET. Based on my experience, if I use IronPython then I can't use python packages like Numpy and Scipy. However, I wanted to see if there is another way to call the .net libraries and be able to use python to implement my control and data analysis algorithms?

Deny client code access to a third-party library in .NET

I am writing a Library using C# and my library uses a third party .NET library. When I roll out my Library I have to include the third-party library as well along with my library. However I want to prevent users of my library (client code) from directly using the third-party library. Is there any way to enforce that at compile time or run time?

If there are no legal issues with doing so, you can use ILMerge to merge the 3rd party library into your own one.
You have the option to make public classes from the 3rd party library internal. This way, clients of your code will not be able to access functionality from the 3rd party library (unless they do some kind of hack. For example, I am not sure if someone can use an internal class using some kind of Reflection code).
Take a look at this article

How to call a c# dll from java program

I have a c# dll that needs to be called in Java.I see that there is a method using jni to call c++ dlls.How can I do it for a c# dll..Please help..I couldnt find any good material on this

From here:-
IKVM.NET is an implementation of Java for Mono and the Microsoft .NET
Framework. It includes the following components:
A Java Virtual Machine implemented in .NET
A .NET implementation of the Java class libraries
Tools that enable Java and .NET interoperability

You can use Java Native Interface. Or you can create a COM assembly from the C# code and use J-Interop to invoke it.
If you have C# dll sources you need to use maybe the better way will be to translate it to Java using some tools like GrassHopper.
According to GrassHopper key feature explanation it can convert MSIL to Java bite code. So can use without sources of c# dll

Check this: http://www.javonet.com
If you look for quick and easy solution then Javonet should work fine for you. It is light counterpart of IKVM and J-Integra works also as native bridge.
All you have to do is:
add Javonet.jar do your project call
call Javonet.addReference("yourlib.dll")
use your .NET library like it was almost JAVA package
Sample:
NObject obj = Javonet.New("yourDotNetClass");
obj.invoke("YourMethod","arg1", 2);
The syntax is not strongly-typed and works like reflection but gives you fastest access to any custom .NET code, third-party libs or .NET framework as no changes are needed on .NET side. If you need it is also possible to implement custom strongly-typed wrappers.
I do recommend this bridge as in my opinion it is easiest to quickly get things done but also other native bridges are worth checking as this is best approach for such case.
I would avoid going into custom JNI or COM unless you have a lot of time and you just want to learn, if you need quick and reliable solution take one of third-party bridges.

C# and Delphi integration

Currently we have couple projects that are written in Delphi 6. Because of specific components that use in these projects (components also written in Delphi 6) it is not easy to convert it in newer version.
As I prefer .NET development and our new products are developed in .NET, I would like to develop new functionalities using these technologies. C# will be programming language.
My question is: How to integrate new functionalities developed in C# with current code in Delphi? Is this good idea at all and what can be possible issues? If someone have similar experience it would be to hear advantages and disadvantages.
I heard for integration in way to develop .dll with C# and use it from Delphi code.
TnX in advance!
Nemanja

You can use COM (ActiveX) both ways.
So Yes, you can make a DLL in C# and mark it as COM-visible and import it into Delphi.
But you cannot use simple (not COM) DLLs this way.

My first port of call would probably be looking into WCF (written in C#) and have Delphi talk to it.
The dll is not a bad idea, but I just think putting it in WCF is more scalable + portable.

COM would probably be my choice. However, if for some reason you wanted to avoid COM you could take a look at the very nifty Unmanaged Exports by Robert Giesecke.
Unmanaged Exports is an MSBuild task that essentially allows you to export static functions from your .Net assemblies to be consumed as ordinary native DLL exports.

You may want to check out Hydra from RemObjects. It permits native and managed code to be used in the same application.
http://www.remobjects.com/hydra/default.aspx

Call Python from .NET

I have some code written in Python which can not be transferred to a .NET language. I need to call one of these functions from my .NET WinForms application.
Now, I do it by starting the Python script as a separate process and pass parameters to it as command line arguments. It works, but I don't really like this solution. I'd like to improve it to a better one.
Is there any better way to call a function of a .py script from a .NET application? What is the best way to do it?
Note: IronPython is NOT an option for this Python script

This might be a lot more work than launching the Python process, but here's an alternate solution.
You can embed Python into another program. The API is for C and Interop from .NET will probably be a major pain. If you're into a bit of a safer way to handle the native Python API, you can look into Boost.Python, which, among its less advertised features, has support for embedding.
With these tools, you can write a C++ managed DLL that uses Boost.Python to load the Python interpreter and execute any Python script. Thus, you can execute any Python code directly in the hosting process, eliminating the use of an external process and any form of IPC.
Edit: AFAIK, all you have to add to your installation procedure is the deployment of the Python DLL and Boost.Python DLL.

Besides the COM option, you could make your Python script instantiate a xmlrpc server -
it is quite transparent and you never have to deal with "xml" on your own code.
Then, on .net side, you simply connect to your python app via xmlrpc - if there is no suitable way to do that in C#, just write a client function in IronPython.
The SimpleXMLRPCServer example on Python documentation is enough for that:
http://docs.python.org/library/simplexmlrpcserver.html

I think you need to re-evaluate Carlos' answer.
See the section Implementing COM Objects with Python in Mark Hammond's book Python Programming on Win32.
You should be able to create a COM object, then have .Net interact with it.
From the book the following will create a COM server with a single method.
# SimpleCOMServer.py - A sample COM server - almost as small as they come!
#
# We expose a single method in a Python COM object.
class PythonUtilities:
_public_methods_ = [ 'SplitString' ]
_reg_progid_ = "PythonDemos.Utilities"
# NEVER copy the following ID
# Use "print pythoncom.CreateGuid()" to make a new one.
_reg_clsid_ = "{41E24E95-D45A-11D2-852C-204C4F4F5020}"
def SplitString(self, val, item=None):
import string
if item != None: item = str(item)
return string.split(str(val), item)
# Add code so that when this script is run by
# Python.exe, it self-registers.
if __name__=='__main__':
print "Registering COM server..."
import win32com.server.register
win32com.server.register.UseCommandLine(PythonUtilities)
The book goes on to say ".. you can do this by executing the code as a normal Python script. The easiest way to do this is to open the source file in PythonWin and use the Run command from the File menu. "
I think you need the ActivePython distribution from Activestate to do it.
See this question Consuming Python COM Server from .NET

It works, but I don't really like this solution, I'd like to improve it to a better one.
No, AFAIK there isn't a better solution, especially if IronPython is a no-no for you. So you could still keep this as a temporary workaround while waiting for the script to be migrated to .NET or until you find that someone already wrote a library on .NET that provides you with similar functionality.

Create a COM .dll from a .py script and use Interop in your .NET code.
Have a look here: http://docs.python.org/faq/windows.html

PythonNet should help with this one. It enables you to call python code from C#.
A cleaner way is to expose the python script via a Flask REST API and consume that from your .NET Application. Don't forget to put proper authentication in place.