Isolated Inventor Add-in Sample

A minimal Autodesk Inventor add-in sample that demonstrates safe dependency isolation. Inventor ships with specific assembly versions. Referencing newer (or different) versions in an add-in often causes binding conflicts. This sample allows the use of NuGet package/assembly versions that differ from the ones bundled with Inventor by isolating the add-in’s dependencies in a custom load context.

Setup

Run Locally

1. Clone this project or download it. It's recommended to install GitHub Desktop. To clone it via command line, use the following:

git clone https://github.com/tylerwarner33/autodesk-inventor-assembly-load-context.git

2. Choose a configuration: Debug-2026, Debug-2025, Debug-2024, Debug-2023 (or the corresponding Release-*) to work with that Inventor version.
3. Build the solution. The post-build step creates a bundle and copies it to (replace <version> and paste in file explorer):
   • %AppData%\Autodesk\Inventor <version>\Addins\IsolatedInventorAddin.bundle\Contents\
4. Run the solution (Inventor will launch automatically using the selected version, as configured in the project file).
5. Use the Serilog Version button to display the version/context of the loaded Serilog assembly.

How It Works

• AddinServer.cs
  • The main entry point for the add-in using the OnActivate() and OnDeactivate() methods. Custom add-in logic added here.
  • Inherits Isolation/IsolatedApplicationAddInServer.cs which implements Inventor.ApplicationAddInServer.
• .NET 8 / Inventor 2025+:
  • Isolation/AddinLoadContext.cs defines a dedicated AssemblyLoadContext and uses AssemblyDependencyResolver so the add-in resolves managed and native dependencies from its own output folder first.
• .NET Framework 4.8 / Inventor 2023–2024:
  • The add-in runs in the default AppDomain. The sample still reports assembly identity to compare behavior across targets.
• The Interop assembly (Autodesk.Inventor.Interop) is referenced with <Private>False</Private> so it’s always loaded from Inventor, while the NuGet dependencies (ex. Serilog) are copied beside the add-in and loaded in isolation.
• The Serilog Version button (SerilogPackageVersionButton) shows the loaded Serilog version and the load context/app domain to verify isolation.
• The project uses MSBuild logic to pick the Inventor version and target framework based on the build configuration.

Resources

• TylerWarner.dev Blog Post: Isolate Inventor Add-In
• Microsoft Learn: System.Runtime.Loader.AssemblyLoadContext
• Microsoft GitHub: AssemblyLoadContext

License

This sample is licensed under the terms of the MIT License. Please see the LICENSE file for more details.