C# .NET Revit API add-in demonstrating use of IExternalCommandAvailability.
Originally implemented for Revit 2011 and described by The Building Coder showing how to enable ribbon items in zero document state.
Migrated to Revit 2019 to answer
the Revit API discussion forum thread
on IsCommandAvailable causing nullref exception.
Jeremy Tammik, The Building Coder, Forge Platform Development, ADN Open, Autodesk Inc.
This sample is licensed under the terms of the MIT License. Please see the LICENSE file for full details.