Detecting Real Block Changes After BlockEdit – Event Issue?

Rhino Developer
, , ,
1

Hi all,

I’m developing a plugin for Rhino (C#, RhinoCommon), and I need to reliably detect when a block (InstanceDefinition) has been truly modified — not just when the BlockEdit command is used, but only when actual changes occur.

Here’s what I’ve tried and found:
What I Want to Detect:

  • When a block is edited using BlockEdit
  • And the user adds, deletes, modifies, or transforms objects inside the block
  • But not trigger if the user just opens BlockEdit and clicks OK without making any changes

Problem:

The InstanceDefinitionTableEventType.Modified event fires even when:

  • The user enters BlockEdit and makes no change, then clicks OK
  • In other words, just confirming the BlockEdit dialog triggers a “Modified” event

This makes it hard to distinguish real changes from no-ops.

**

Is there a more reliable way to detect actual changes in a block definition after BlockEdit?

**
Thanks in advance!