RhinoCommon Event handler issue

Rhino Developer
1

Hi,
I am facing an issue with event handlers. Let’s say there are 2 Rhino plugins, plugin A and plugin B. Both have an event handler for Rhino.Commands.Command.BeginCommand. When I run “BlockEdit” command, plugin A crashes due to a bug, and when this happens, the plugin B doesnt handle the event anymore.
I am working on plugin B, and the issue I am having is that when some other plugin is crashing when handling the event, my code doesnt get executed. And sometimes I am not sure which plugin is crashing when handling events. Is this a bug? Is there a work around for this?

1 Like
2

Lol, well yes - in the plug-in that is crashing. I don’t think there is anything we can do about this…

– Dale

3

Yes definitlely. This time I could find that out, as both the plugins were written by me. But I was wondering how to track this if at all it is a third party plugin that is crashing. There is generally no warning when this happens.

4

Yep, this is my experience as well. When working with events it is either working or it crashes Rhino.

5

Hi @Darryl_Menezes,

We always advise developers to not do too much in event handlers, especially document modifications. It’s better to set a flag and then handle the event later in a Rhino.Idle handler.

Here is a pattern I use frequently:

/// <summary>
/// Event handlers
/// </summary>
private EventHandler<DocumentEventArgs> m_new_document;
private EventHandler<DocumentOpenEventArgs> m_end_open_document;
private EventHandler m_idle;

/// <summary>
/// Event type
/// </summary>
enum EventType
{
  None,
  NewDocument,
  EndOpenDocument,
}
private EventType m_event_type;

/// <summary>
/// Hook Rhino events
/// </summary>
private void HookRhinoEvents()
{
  if (null == m_new_document)
    RhinoDoc.NewDocument += m_new_document = OnNewDocument;

  if (null == m_end_open_document)
    RhinoDoc.EndOpenDocument += m_end_open_document = OnEndNewDocument;
}

/// <summary>
/// Unhook Rhino events
/// </summary>
private void UnhookRhinoEvents()
{
  if (null != m_new_document)
  {
    RhinoDoc.NewDocument -= m_new_document;
    m_new_document = null;
  }

  if (null != m_end_open_document)
  {
    RhinoDoc.EndOpenDocument -= m_end_open_document;
    m_end_open_document = null;
  }
}

/// <summary>
/// Hook Rhino.Idle event
/// </summary>
private void HookRhinoIdle(EventType eventType)
{
  if (null == m_idle)
  {
    m_event_type = eventType;
    RhinoApp.Idle += m_idle = OnIdle;
  }
}

/// <summary>
/// Unhook Rhino.Idle event
/// </summary>
private void UnhookRhinoIdle()
{
  m_event_type = EventType.None;
  if (null != m_idle)
  {
    RhinoApp.Idle -= m_idle;
    m_idle = null;
  }
}

/// <summary>
/// RhinoDoc.NewDocument event handler
/// </summary>
private void OnNewDocument(object sender, DocumentEventArgs args)
{
  HookRhinoIdle(EventType.NewDocument);
}

/// <summary>
/// RhinoDoc.EndNewDocument event handler
/// </summary>
private void OnEndNewDocument(object sender, DocumentOpenEventArgs args)
{
  HookRhinoIdle(EventType.EndOpenDocument);
}

/// <summary>
/// RhinoApp.Idle event handler
/// </summary>
private void OnIdle(object sender, EventArgs e)
{
  switch (m_event_type)
  {
    case EventType.NewDocument:
      {
        // todo
      }
      break;
    case EventType.EndOpenDocument:
      {
        // todo
      }
      break;
  }
  UnhookRhinoIdle();
}

Hope this helps,

– Dale

3 Likes
6

Hi @dale,

Suppose you’re executing a script, will OnIdle be triggered during the execution of the script?

7

It can be if you add the event handler to the sticky settings.

SampleEventHandler.py

– Dale

1 Like
8

Yes, I use a modified version of this, still if you do something as little as having a typo, result will be crashing Rhino.