Tools and operations use commands to change the uDig model. Commands are used to change the model so that undo/redo operations are supported.
If you notice the IContext objects provide references to ILayer, IMap, IViewportModel, etc... which are all read only interfaces. Commands have access to Map, ViewportModel and Layer interfaces which permit writes. So if you write a command you can use it to change the state of the model. But before you write a command check to see if the command exists because they all (or almost all) have undo implementations written and will save you some work. You can get the list of available commands by using the SelectionCommandFactory, EditCommandFactory and NavigationCommandFactory. Jesse On Wed, 2005-11-30 at 10:36 +0000, Iñigo Telleria Elola wrote: > Hi, > I have read the programmer guide and this document explains the commands > type and how to create. But I would like to know how I can use, what > sentence I have to write. And I dont't know in which cases I have to use a > command or a tool or an operations... I'm confused. > > > _______________________________________________ > User-friendly Desktop Internet GIS (uDig) > http://udig.refractions.net > http://lists.refractions.net/mailman/listinfo/udig-devel _______________________________________________ User-friendly Desktop Internet GIS (uDig) http://udig.refractions.net http://lists.refractions.net/mailman/listinfo/udig-devel
