@gemiko thanks for trying pythonnet! Search this issue tracker for %pythonhome% examples.

here is wiki entry about:

https://github.com/pythonnet/pythonnet/wiki/Troubleshooting-on-Windows-and-Linux#cpython-27-36-installed

I attempted to follow this #259 (comment), under my VS2015 environment to set the paths, but didn't work. Setting PYTHONHOME in my system environmental variable to C:\Users\username\Miniconda3\envs\anaconda3 also did not work.

The only way PythonNet works for me is by using the root Anaconda environment, which isn't a solution when when I have to manage multiple projects that have their own package requirements which is why I'm using Conda environments.

Any other potential solutions?

@gemiko did you activate your env. before calling it for embedding in .NET at runtime? what errors and tracebacks did you get? what does conda env list show?

Finally before PythonEngine.Initialize() call you can set PythonHome property:

Inside the commandline, activating the conda environment and then starting visual studio works.

However, when deploying the software, I found I absolutely needed to set the PYTHONHOME and PYTHONPATH environment variables. The good thing is that Conda Python environments are standalone and can be deployed with your application. It's just a matter of how to package it all together.

Suppose the Python 3.5 environment should be stored in a subdirectory named "Python" one level from the exe, this worked for me:

string exeDir = AppDomain.CurrentDomain.BaseDirectory;
string envPythonHome = exeDir + @"Python";
Environment.SetEnvironmentVariable("PYTHONHOME", envPythonHome, EnvironmentVariableTarget.Process);
Environment.SetEnvironmentVariable("PATH", envPythonHome, EnvironmentVariableTarget.Process);

Adding the following to the Post-Build event command line will mirror the Python environment to the build output directory and complete the build process (Robocopy error codes < 8 are not errors and need to be set to 0 for Visual Studio builds to be successful):
(robocopy "Path to Python Environment Directory" "$(TargetDir)Python" /MIR) ^& IF %ERRORLEVEL% LEQ 7 SET ERRORLEVEL=0

Hope this helps others!

@gemiko would you mind summarizing your tutorial in wiki? this is great resource asked many times here!

Unfortunately, it stopped working for me. I'll need to investigate it some more.

Looks like I got it working now. Setting both the PATH and PYTHONHOME to the directory is needed. I'll also edit the above post so there's no confusion for others.

string exeDir = AppDomain.CurrentDomain.BaseDirectory;
string envPythonHome = exeDir + @"Python";
Environment.SetEnvironmentVariable("PYTHONHOME", envPythonHome, EnvironmentVariableTarget.Process);
Environment.SetEnvironmentVariable("PATH", envPythonHome, EnvironmentVariableTarget.Process);

This looks solved, feel free to reopen if that isn't the case.

Hi Everyone,

I tried every possible thing written on this page but nothing worked. Still getting this issue
System.DllNotFoundException: 'Unable to load DLL 'python35': The specified module could not be found. (Exception from HRESULT: 0x8007007E)'
I have download pythonnet and python3.5 nuget package and trying to embed python in >net environment.

Please help

Thanks,
Divya

@shrishar i don't think anyone tested the python3.5 nuget package with pythonnet, but there should not be anything special about it. just make sure to match the architecture x86/x64.

Is there any additional documentation on how to call python FROM C#? I have struggled with everything listed here and still cannot get this working. I have installed pythonnet into a python 3.6 environment running in Conda. I can access the clr FROM python, but really need to call python FROM C#.

I finally found that I needed to include "Python.Runtime.dll", but it was unclear from WHERE (I found it here: "C:\Anaconda\envs\cvpy36\Lib\site-packages" and assume that is what I need. (It would be helpful to include this information on the main pythonnet documentation page).

I was able to get through the "Unable to load DLL" errors by using the code that gemiko supplied above, but now as soon as I call PythonEngine.Initialize() the application quits (no errors, no messages, nothing).

Any suggestions, or link to more detailed step-by-step instructions on how to make this work in C# (something that includes adding the correct references, "using" statements, etc.)?

Thanks!

---- EDIT ----

I found the issue and want to leave this here for others.

It seems you have to set the environment variable, but you ALSO need to set PythonHome for the PythonEngine (I assumed this would get set from the environment variable, as PythonEngine cannot be called without it).

Adding the line:

PythonEngine.PythonHome = "C:\\Anaconda\\envs\\cvpy36";

fixed it.

@GafferMan yes, and anaconda can mess up few other things when embedding its Python via pythonnet. I prefer to use vanilla CPython for embedding use cases. There are now wheels for almost any packages, albeit not highly optimized.

@shrishar i don't think anyone tested the python3.5 nuget package with pythonnet, but there should not be anything special about it. just make sure to match the architecture x86/x64.

Oh, Jesus Christ.
The only point for me was the architecture type!

My working solutions:
HERE_01
HERE_02