I've known AutoCAD to throw an exception when attempting to use entmod within a reactor callback function under certain circumstances, and so this could very well be the cause of your error.
Note that you cannot invoke a command call from within a reactor callback function, therefore a post-process evaluation using the sendcommand method is required.I did the conclusion that they work OK only with ActiveX (as you mentioned above: use vla-sendcommand instead of command, and avoid any entity-manipulation functions)
For what it's worth, below is an old example from my library which performs the same operation:Thank you! As a reactor newbie I appreciate it, since its not easy to determine where and how the error occured while using some reactor.
You may also be interested in this utility (http://bit.ly/1MwdLSu) as another example of performing operations triggered on object selection.Yes, I clearly remember this thread
Quote from: Lee MacNote that you cannot invoke a command call from within a reactor callback function, therefore a post-process evaluation using the sendcommand method is required.
I did the conclusion that they work OK only with ActiveX (as you mentioned above: use vla-sendcommand instead of command, and avoid any entity-manipulation functions)
I knew that I could use vla-sendcommand with CHPROP from there...
The use of vla-sendcommand does enable you to perform post-process operations, but if presented with multiple ways to achieve the same result, I would generally avoid this method unless there is no alternative.
the supporting code needs to be watertight, accounting for every possibly eventuality to ensure uninterrupted operation.