ansys-pythonnet

3.1.0rc6 verified Fri May 01 auth: no python

Ansys fork of pythonnet providing .NET and Mono integration for Python. Version 3.1.0rc6, targeting Python 3.7-3.13. Active development with release candidate status.

pip install ansys-pythonnet

Common errors

error ImportError: No module named clr ↓

cause Missing ansys-pythonnet package or mistakenly installed old pythonnet package which does not expose clr.

fix

Install ansys-pythonnet: pip install ansys-pythonnet

error AttributeError: module 'clr' has no attribute 'AddReference' ↓

cause Using 'import clr' but not loading the module correctly; possibly a namespace conflict or incomplete install.

fix

Ensure ansys-pythonnet is installed and imported as 'import clr'. Check for clr files shadowing from other packages.

error System.BadImageFormatException: Could not load file or assembly ... ↓

cause Mismatch between Python architecture (32-bit vs 64-bit) and .NET assembly target.

fix

Ensure both Python and .NET runtime use the same bitness. Use 64-bit Python with 64-bit .NET assemblies.

Warnings

breaking The PythonNET (pythonnet) fork renamed to ansys-pythonnet. Import statements remain 'import clr' but package name changed. Existing code using 'pythonnet' package will not work; reinstall with 'pip install ansys-pythonnet'. ↓

fix Replace 'pythonnet' with 'ansys-pythonnet' in requirements.txt and environment.

deprecated clr.AddReference works, but the newer recommended approach uses 'import clr' and then 'clr.AddReference' with assembly names. Avoid loading assemblies via absolute paths if possible. ↓

fix Use assembly name without extension: clr.AddReference('System.Windows.Forms') instead of path.

gotcha Python 3.13 is not fully supported yet; current version supports <3.14,>=3.7 but only tested up to 3.12. Use Python 3.12 or earlier for stable behavior. ↓

fix Use Python 3.12 or earlier. Check official repo for updates.

Install

pip install ansys-pythonnet==3.1.0rc6

Imports

clr
wrong
```
import pythonnet
```
correct
```
import clr
```
pythonnet is the package name; the top-level module is clr.
System
wrong
```
import System
```
correct
```
from System import Array, String
```
Use from System import ... to import specific .NET types.

Quickstart

Basic usage: import clr, add a .NET assembly reference, and import .NET namespaces.

import clr
# Add reference to a .NET assembly
clr.AddReference('System.Windows.Forms')
from System.Windows.Forms import MessageBox
MessageBox.Show('Hello from .NET!')