Mailman 3 September 2018 - 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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Using PyScope to set variables I can use in imported scripts
by Luke, Steve Sept. 24, 2018

Sept. 24, 2018

I am new to Python.Net and trying to convert an application that used IronPython to embed a Python environment into a .Net application and allow the user to run Python scripts inside our application. The part that embeds the Python environment is VB.Net (but could be C# if that would be better). I am running into problems setting variables in the scope such that they can be used in the Python scripts we call. I keep getting an error: NameError: global name 'Bridge' is not defined. This is the VB code I am trying to use: PythonEngine.Initialize() Using (Py.GIL()) Dim moduleName As String = "PrintToBridge" Dim pythonCommandLine As String = "Not used yet" Dim scope As PyScope = Py.CreateScope() Try scope.Set("Bridge", bridge) scope.Set("SetupParams", cmdLine) Dim script As Object = scope.Import(moduleName) bridge.mm.PrintMsg("Scope has Bridge:" + Str(scope.Contains("Bridge"))) script.Startup(pythonCommandLine) Finally scope.Dispose() End Try End Using The Python script: def Startup(param): Bridge.mm.PrintMsg('Startup called') def Docommand(param): Bridge.mm.PrintMsg('docommand called') def Shutdown(): Bridge.mm.PrintMsg('Shutdown called') How can I set a variable such that it would be recognized by the called Python script? Importing the script works, I can force python-y things to happen. And the check to see if the object I want is in scope returns true. But it still isn't available in Python. I have tried scope.Eval(moduleName + ".Startup('" + pythonCommandLine + "')") and Exec() with locals: Dim locals As PyDict = New PyDict() locals.SetItem("Bridge".ToPython(), bridge.ToPython()) scope.Exec(moduleName + ".Startup('" + pythonCommandLine + "')", locals) All with the same effect. Any ideas on how to get set variables so scripts can gain access to them? Thanks, Steve Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.

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Invoking a C# method with a python list
by Mohamed Koubaa Sept. 24, 2018

Sept. 24, 2018

Hello, I am using the 2.3 release branch. I have C# code like this: public class A { public A() {...} } public class B { public B() {...} public static void Func(IEnumerable<A> input){ } } I want to pass in a python list to Func but get this error: >>> b=B() >>> b.Func([A(), A()]) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: No method matches given arguments I tried both IEnumerable and IList in the signature of 'Func'. I know that I can import System and create some .NET collection type and it works well. Did I miss anything? Is this usage pattern within the design goals of pythonnet? I assume this would have to be fixed in MethodBinder but I wanted to try asking here first. Thanks! Mohamed Koubaa

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