What are Events and Event Triggers?

Event is an action, which can be detected by the software. It's like a notification mechanism that can tell us that something has happened.

Event Trigger is what actually causes the event. For instance if user would click on "Import CAD", it can trigger an event of clicking this button.

Event Handler - is a piece of code that will be executed once event is triggered.

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For example:

• User click on Import CAD button (Event Trigger)

• Software detect the action (Event)

• Our code is triggered (Event Handler)

In this example, event can help us monitor when users click on the "Import CAD" button and give them a warning message saying that we don't like when they use it. We can even set a password so users can't use it without it.

How to work with Events?

Events in Revit API can be tricky. You have to subscribe and unsubscribe manually and it becomes tedious task to manage because events will be remembered in your projects.

Here is an example for reference: (No need to execute!)

Events in pyRevit (hooks).

However, pyRevit has a very unique approach to events.

You can create hooks folder in your .extension and then place scripts for the events, and pyRevit will subscribe and unsubscribe to them for you.

The key here is to use the correct naming for you files, as pyRevit will use the name of the file to subscribe to the correct event.

Here is a folder structure example:

You can read more about the hook file naming here in pyRevit Docs. Here is an example of the table:

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💡 pyRevit also has a short guide on How To Create Your First Hook.

pyRevit Hook Example

​Click Here to watch a tutorial about pyRevit Hooks.

In this video I will show you how to prevent users from using Import CAD command in Revit and how you can set a password to this command in Revit.