Mailman 3 May 2016 - Python.NET

Multithreading/multiprocessing
by Alan Macdonald May 5, 2025

May 5, 2025

Hello, has anyone successfully used multithreading or multiprocessing with Python.Net? I tried to multi-thread from the .Net side and the Python.Net libraries seem to have issues in the RunScript method. I had to take an implementation off the web of that method because the shipped method doesn’t seem to work. I then had a working multi-processing example from CPython that I tried from Python.Net but it gives an error 'module' object has no attribute 'argv' When trying to create a process pool by executing the line pool = Pool(processes=4) Is it possible to do multithreading or multiprocessing with Python.Net? Thanks, Alan

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PythonNet on Cygwin
by Nikhil Garg June 21, 2017

June 21, 2017

Hi Guys, I was wondering if anyone knows how to make Python for .Net work on cygwin installation of python. I have been looking around and find a mixed bag of information. If anyone knows of the working version of Python for .Net and its dependency, I would appreciate if you could share it with me. Currently, I am using a generic windows version and it works just fine, but I need it to work on Cygwin version of python. I appreciate any helpful replies. Thanks, Nikhil

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cx_freeze and python.net
by Boris Burdin May 22, 2017

May 22, 2017

Hello everybody, I'm trying to build a python.net application using cx-freeze . Once the application is built, I put in my final folder the Python.Runtime.dll. but it stil doesn't seem to work . Actually, when I run the .exe file, nothing is happening. So, I wonder if there were something else to do, another dll to put in the folder, or any option to use with cx_freeze when building the application ? i would be very grateful if you could help me on this matter .. Thanks in advance, Boris

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pythonnet appdomain(s)
by Adam Klein Sept. 7, 2016

Sept. 7, 2016

Hello, Is there a design reason that pythonnet loads C# assemblies into its own AppDomain rather than establishing a separate AppDomain? It would be useful for instance when developing in C# in parallel with writing python code (say, in the ipython REPL) to be able to reload C# assemblies dynamically. Also, we've found it useful in Initialize() to enable shadow copying, to prevent file locking, ie internal static void Initialize() { ... AppDomain domain = AppDomain.CurrentDomain; // prevent file locking domain.SetShadowCopyFiles(); domain.SetShadowCopyPath(null); Although these are deprecated methods, and really it should be establishing a new AppDomain as above. Regards, Adam _________________________________ Adam D Klein BlueMountain Capital Management LLC 280 Park Ave, 5th Floor East New York, NY 10017 O:(212)905-2136 C:(917)331-8871

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"Incorrect" behavior of inheriting from class which is inherited from .Net class
by Hansong Huang Aug. 25, 2016

Aug. 25, 2016

Hello, This is related to previous investigation of inheriting from .NET interface class to create WPF MVVM structure. As now I believe it has nothing to do with interface class, but instead caused by inheriting from .Net class overall. please see the following code import clr, Systemclass baseNA(System.Random): __namespace__ = "BaseNA" def __init__(self): super(baseNA,self).__init__()# @clr.clrmethod(System.String,[]) def ToString(self): return "string" class baseNB(baseNA): __namespace__ = "BaseNB" def __init__(self): super(baseNB,self).__init__()bna = baseNA()print bna.ToString()print bna._Random__ToString()bnb = baseNB()print bnb.ToString()print bnb._baseNA__ToString()print bnb._Random__ToString() This produces the following outputstringBaseNA.baseNABaseNB.baseNBBaseNB.baseNBBaseNB.baseNB as you see, while baseNA -- the first level inherited class works fine. ToString() overrides System.Random.ToString() But baseNB inherited from baseNA did not inherit ToString() method from baseNA, but rather inherited from System.Random. Not sure if it is a bug in python.net or was intended. regards, Hansong

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pyinstaller + pythonnet
by Nikhil Garg June 19, 2016

June 19, 2016

Hi All, I tried to build a very simple executable using pyinstaller, where my script just imported clr module. I managed to build the executable but then the executable doesnt run. I have posted the error below. I think the executable is able to find the runtime dll but it is unable to run it. Unhandled Exception: System.IO.FileLoadException: Could not load file or assembl y 'Python.Runtime, Version=4.0.0.1, Culture=neutral, PublicKeyToken=5000fea6cba7 02dd' or one of its dependencies. The located assembly's manifest definition doe s not match the assembly reference. (Exception from HRESULT: 0x80131040) at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String cod eBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntro spection, Boolean suppressSecurityChecks) at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName as semblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMar k& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIn trospection, Boolean suppressSecurityChecks) at System.Reflection.Assembly.Load(AssemblyName assemblyRef) at clrModule.initclr() I would appreciate any help

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Explicitly implemented interface methods
by Henning Moeller May 31, 2016

May 31, 2016

Hello out there, I've come across an issue with calling a method of an instance which ends up being an explicitly implemented interface method. Let me explain with a very brief example: Consider this a very basic interface: [File: ISomeInterface.cs] namespace PythonInterfaceCalls { public interface ISomeInterface { void ImplicitImplementation(); void ExplicitImplementation(); } } And here's an implementing class. Note one of the methods being implicitly implemented, the other being explicitly implemented: [File: SomeImplementation.cs] using System; namespace PythonInterfaceCalls { public class SomeImplementation: ISomeInterface { public void ImplicitImplementation() { Console.WriteLine("Call of implicitly implemented interface method."); } void ISomeInterface.ExplicitImplementation() { Console.WriteLine("Call of explicitly implemented interface method."); } } } Note the method headers. While the implicit implementation is (and has to be) public, the explicit implementation is (and has to be) internal. Both methods work well in C# (as long as the instance is casted into the interface type). See the unit tests, both passing: [File: TestImplementation.cs] using System; using System.IO; using NUnit.Framework; namespace PythonInterfaceCalls { [TestFixture] public class TestImplementation { [Test] public void TestImplicitCall() { var implementation = new SomeImplementation() as ISomeInterface; using (StringWriter sw = new StringWriter()) { Console.SetOut(sw); implementation.ImplicitImplementation(); Assert.AreEqual("Call of implicitly implemented interface method.\r\n", sw.ToString()); } } [Test] public void TestExplicitCall() { var implementation = new SomeImplementation() as ISomeInterface; using (StringWriter sw = new StringWriter()) { Console.SetOut(sw); implementation.ExplicitImplementation(); Assert.AreEqual("Call of explicitly implemented interface method.\r\n", sw.ToString()); } } } } This should be solvable using the following method to access all interface members, not just the publicly available ones: [File: InterfaceMembersExtension.cs] using System; using System.Collections.Generic; using System.Reflection; namespace PythonInterfaceCalls { public static class InterfaceMembersExtension { public static IList<MethodInfo> GetImplementedMethods(this Type targetType, Type interfaceType) { return targetType.GetInterfaceMap(interfaceType).TargetMethods; } } } Please find the complete solution attached to this mail. Is there a chance that this will be implemented in PythonNet? Thanks in advance, Hennnig

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Issue with beautifulsoup 4
by Daniel Fernandez May 31, 2016

May 31, 2016

Hey Everyone, I'm running into an issue importing beautifulsoup 4 only if I import clr before importing beautifulsoup. I'm using python 3.5 32-bit version on my Windows 7 and Windows 10 box. I'm using beautifulsoup package from Gohlke website (beautifulsoup4-4.4.1-py3-none-any.whl) I simply runimport clrfrom bs4 import beautifulsoup then I get this error Unhandled Exception: System.ArgumentException: Name must not be empty! at Python.Runtime.ModuleObject..ctor(String name) at Python.Runtime.ModuleObject.GetAttribute(String name, Boolean guess) at Python.Runtime.ImportHook.__import__(IntPtr self, IntPtr args, IntPtr kw) at Python.Runtime.Runtime.PyObject_Call(IntPtr pointer, IntPtr args, IntPtr kw) at Python.Runtime.ImportHook.__import__(IntPtr self, IntPtr args, IntPtr kw) at Python.Runtime.Runtime.PyObject_Call(IntPtr pointer, IntPtr args, IntPtr kw) at Python.Runtime.ImportHook.__import__(IntPtr self, IntPtr args, IntPtr kw) I build the pythonnet debug version I get this call stack Unhandled Exception: System.ArgumentException: Name must not be empty! at Python.Runtime.ModuleObject..ctor(String name) in pythonnet\src\runtime\moduleobject.cs:line 26 at Python.Runtime.ModuleObject.GetAttribute(String name, Boolean guess) in pythonnet\src\runtime\moduleobject.cs:line 101 at Python.Runtime.ImportHook.__import__(IntPtr self, IntPtr args, IntPtr kw) in pythonnet\src\runtime\importhook.cs:line 315 at Python.Runtime.Runtime.PyObject_Call(IntPtr pointer, IntPtr args, IntPtr kw) at Python.Runtime.ImportHook.__import__(IntPtr self, IntPtr args, IntPtr kw) in pythonnet\src\runtime\importhook.cs:line 237 at Python.Runtime.Runtime.PyObject_Call(IntPtr pointer, IntPtr args, IntPtr kw) at Python.Runtime.ImportHook.__import__(IntPtr self, IntPtr args, IntPtr kw) in pythonnet\src\runtime\importhook.cs:line 237 if I switch the lines of codefrom bs4 import Beautifulsoupimport clr no errors occur. Is anyone running into this issue? Thanks. Danny

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Embedding a Python interactive shell in a .NET application
by Saparya K May 28, 2016

May 28, 2016

Hello PythonNet, I am looking to embed a Python interactive (REPL) shell in a .NET WinForms application. This C# application displays a graphical visualization of some data. Methods to manipulate the data in the C# application would be exposed via a Python API. The idea is to be able to interact with the data from the Python shell via the API, and thereby updating the graphical view. Ideally, the shell should support any valid Python syntax that is required to use the API. This would involve: 1. Querying a collection of data from the application via the Python API 2. Then manipulating this collection in the Python shell 3. Making API calls with the modified collection as an argument I came across a few examples where an interactive shell was developed using IronPython. A limitation with this approach is the absence of *Python 3.x* support (and other C-compiled libraries) in IronPython. For this reason, I would prefer to use Python.NET if it is possible. Has anyone here tried something like this with Python.NET before? Does it looks like what I am trying to achieve is feasible? Any direction would be very helpful!

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Interesting 2015 video from long-time pythonnet user at JP Morgan Chase
by Denis Akhiyarov May 26, 2016

May 26, 2016

Today I stumbled upon an interesting video from last year by Maksim Kozyarchuk, who is Director at JPMorgan Chase & Co. in New York. He is long-time pythonnet user - as early as 2006! https://mail.python.org/pipermail/pythondotnet/2006-August/000544.html He described how they built WPF GUI applications using pythonnet. https://www.youtube.com/watch?v=0xfLo7PpKPc http://pyvideo.org/video/3774/writing-winforms-and-wpf-applications-in-pyth… You can follow his blog at http://kozyarchuk.blogspot.com/ -- Denis

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