Mailman 3 March 2015 - 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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changes to Python.Runtime.Converter and Python.Runtime.Object
by Cameron Hayne March 26, 2015

March 26, 2015

I have been using the version of PythonDotNet from https://github.com/renshawbay/pythonnet for embedding - i.e. to call Python code in C# programs. I have made a few changes to the source code in order to make using Python objects in C# easier, or to fix problems. Here are the changes: 1) In the source file “converter.cs” which defines the class Python.Runtime.Converter, I added the following to the switch case ‘TypeCode.Object’ in the ‘ToPython’ function: case TypeCode.Object: // The following ‘if’ clause is needed (as suggested by Patrick Stewart) to make the examples in the README work. if (value is IEnumerable) { using (var resultlist = new PyList()) { foreach (object o in (IEnumerable)value) { Type oType = o.GetType(); TypeCode oTc = Type.GetTypeCode(oType); // The following 'if' clause for Object entries is needed so that the entries // in lists of Python objects don't lose their types. // I.e. so that if you do something like: // dynamic obj1 = myPythonClass(); // List<dynamic> myList = new List<dynamic> { obj1 }; // myPythonFunc(myList); // then the type of myList[0] inside myPythonFunc will be the same as the type of obj1 // whereas the 'else' clause would make it be of type Python.Runtime.PyObject if (oTc == TypeCode.Object) { resultlist.Append((PyObject)o); } else { using (var p = new PyObject(ToPython(o, oType))) resultlist.Append(p); } } Runtime.Incref(resultlist.Handle); return resultlist.Handle; } } 2) In the source file “pyobject.cs” which defines the class Python.Runtime.PyObject, I replaced the line: this.SetAttr(binder.Name, (PyObject)value); in the ‘if (this.HasAttr(binder.Name))’ clause in the function ‘TrySetMember’ with the following: // Use ‘ToPython’ if an exception occurs when casting to (PyObject) // Without this, get exception e.g. when assign a C# String to a Python member // like: myPyObj.name = name; PyObject pyValue; try { pyValue = (PyObject)value; } catch (Exception) { pyValue = value.ToPython(); } this.SetAttr(binder.Name, pyValue); I would be interested in any comments about these changes - especially if there are better ways of fixing the problems. I am also interested to hear if anyone has other improvements to suggest. -- Cameron Hayne cameron.hayne(a)introspect.ca

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About use DotNet threading lib
by Longhui Xiong March 4, 2015

March 4, 2015

Hi there, I am using python for DotNet, I have to say, it is great. As we know, cpython has the Global Interpreter Lock (GIL) on multi-threading. So it can not use multi-core. So I have one question, if I import CLR and use System.Threading on python for .net, but don't use cpython threading, My question: Does it still has GIL on multi-threading if I use DotNet threading lib? Can it use multi-core use DotNet threading lib. I know IronPython has no GIL and multi-threaded code can use multi core processors. So I pay attention this issue, on python for dotnet, if I use DotNet threading lib instead of cPython threading lib, Can multi-threaded code use multi core, it still has GIL? I look forward to your reply. Regards

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