IApplication reference with ArcObjects Class Extension

Question

I have an ArcObjects (9.3) Class Extension which has an event handler for OnCreate so that feature properties can be manipulated / assigned when a feature is first created.

Some of the functionality needs enclosing in an edit operation, which requires an IWorkspaceEdit object. As far as I know the only way I can get the IWorkspaceEdit is by getting the IEditor (extension) from IApplication, then grabbing the IEditor's EditWorkspace.

In an ArcObjects command (extending BaseCommand) I get the IApplication 'hook' passed on create (that is, the command's creation), so I can retain a reference to it. However, in the class extension's OnCreate method I am only passed the IObject which has been created. I can't see a way to get the IObject's workspace to work from that direction.

Can anybody please tell me

1. How to access the calling IApplication from a class extension or,
2. How to get an IObject's EditWorkspace or,
3. Any other way to create an edit operation within a class extension's OnCreate method?

Any help very much appreciated.

Answer 1

You can cast an IObject.Table to IDataset, then cast IDataset.Workspace to IWorkspaceEdit. If you only intend for people using a desktop app to edit the data, I agree with @Jamie that you consider an edit extension instead. The advantage of a class extension is that it will receive events even when used in a standalone (arcengine) application (though I've never tried this). For that reason, you should not have any dependencies on IApplication.

Answer 2

I would recommend you make an editor extension if you want to manipulate editing events. Using the IWorkspaceEdit just adds complication. Here is a link to the ESRI editor extension help.

http://resources.esri.com/help/9.3/ArcGISDesktop/dotnet/930daa9a-89fe-4899-a7f4-dd1b520ad316.htm