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C# Scripts

Use C# scripts when you want a short typed snippet without creating a full add-in project.

Entry suffix:

*script.csx

Example:

samples/CSharpScriptDemo/main_script.csx

NuGet References​

Declare package references with Roslyn #r directives:

#r "nuget: Newtonsoft.Json, 13.0.3"
#r "C:/Program Files/Autodesk/Revit 2025/RevitAPI.dll"
#load "./Helpers/DocumentHelper.csx"

#r "nuget: …" resolves through the shared NuGet resolver (NugetManager). Packages restore under %APPDATA%\RevitDevTool\nuget. Host API paths can be rewritten by the host bridge.

#load pulls additional .csx files into the script graph. Each file can declare its own #r and #load directives.

Host Version Symbols​

Scripts receive the same preprocessor symbols as host add-in projects (REVIT2025, REVIT2025_OR_GREATER, AUTOCAD2026, and so on) via CompileScriptSymbols. Use #if REVIT2025_OR_GREATER in .csx the same way you would in a compiled add-in.

Debugging​

C# scripts compile with Debug emit and a portable PDB so an attached debugger can bind breakpoints to the original .csx source.

Workflow:

  1. Open the script folder in Visual Studio or VS Code (C# Dev Kit recommended).
  2. Set breakpoints in your .csx files.
  3. Attach the debugger to the running host process (Revit.exe, acad.exe, …).
  4. Run the script from RevitDevTool.

C# script debugger

Placeholder — replace with a product screenshot.

For attach settings shared with F# scripts and assemblies, see Attach Debugger.

Samples​

samples/CSharpScriptDemo/
samples/AcadCSharpDemo/   (AutoCAD-family)