Document focus event, c#

Replies to This Discussion

Permalink Reply by David Rutten on November 21, 2014 at 11:50am

The GH_Canvas has a DocumentChanged event that tells you both the document that was loaded before and the one that got loaded just now.

Permalink Reply by Tree on November 21, 2014 at 5:06pm

David,

I'm having some difficulty. For some reason I cannot produce a method that I can subscribe to that refers to DocumentChanged.

As an example I am using methods like this (below) to trigger processes. Is it possible to use this form with document changed - if not what form should I be using?

private void DocumentRemoved(GH_DocumentServer sender, GH_Document doc)
{
//Code
}

via

Grasshopper.Instances.DocumentServer.DocumentRemoved += DocumentRemoved;

Permalink Reply by David Rutten on November 22, 2014 at 2:55am

The event tells you the signature you need to use to handle it. It should look like:

void DocumentChanged(GH_Canvas sender, GH_CanvasDocumentChangedEventArgs e)

{

  // Your code here...

}

Permalink Reply by Tree on November 23, 2014 at 1:03pm

David,

Understood, I should have been more specific. My problem seems to sit in the namespace with neither GH_Canvas or GH_CanvasDocumentChangedEventArgs being recognized either when I make the method or when I try to make an event to subscribe to (no recognizable tab complete for example) what am I doing wrong?

Permalink Reply by David Rutten on November 23, 2014 at 1:42pm

Those classes are defined in Grasshopper.GUI.Canvas

So unless you've imported that namespace, you'll have to prefix that to any class.

Permalink Reply by Tree on November 23, 2014 at 2:11pm

David,

Yes, I understand that and am looking at the prefix Grasshopper.GUI.Canvas which then lands me with the following difficulty which is - what does the subscription look like? I'm not having luck with it.

Permalink Reply by David Rutten on November 23, 2014 at 5:08pm

Since it's not a static event, you'll first have to get an instance of the canvas class. Typically there's only one canvas and you can reach it via the Instances class:

GH_Canvas canvas = Grasshopper.Instances.ActiveCanvas;

It may be null if the window has never been loaded or if the GrasshopperUnloadPlugin command was run.

Then you can register your handlers with this instance:

canvas.DocumentChanged += MyDocChangedEventHandler;