使用 Pythonnet 从 C# 调用 Python 会引发导入错误

Question

I have a use case where I want to be able to call a function which is written in Python from my C# code base. When I make a call to this function I want to be able to pass C# types(custom classes) to Python function and for that I was exploring pythonnet .

Python project has a following sample structure -

main.py
service1.py

main.py has the main function which calls the methods exposed by service1.py -

from Service1 import MyService1

def Run(a, b):
   service1 = MyService1()
   service1.method(a, b)

Now from C# side when I try to execute the Python it is throwing error -

Python.Runtime.PythonException: 'No module named 'Service1''

C# code -

Runtime.PythonDLL = @"C:\Program Files\Python39\Python39.dll";
PythonEngine.Initialize();
using (Py.GIL())
{
  using (var scope = Py.CreateScope())
  {
     scope.Exec(File.ReadAllText(@"..\Python\main.py"));
   }
 }

How do I need to import the required classes correctly?

Answer 1

I was running into this issue because my Python scripts were not part of the build folder. I had to ensure that the required Python files are part of the build folder on the successful build of the solution.

To make a file part of your build folder you will need to - Right click on file in VS -> Properties -> Copy To Output directory -> select Copy Always or Copy if newer.

Alternatively, you can do this from.csproj file as well.