public Result Execute( ExternalCommandData commandData, ref string message, ElementSet elements) { UIApplication uiapp = commandData.Application; UIDocument uidoc = uiapp.ActiveUIDocument; Document doc = uidoc.Document; Result rslt = Result.Failed; string name = "TrackChanges_project_identifier"; Guid named_guid; bool rc = JtNamedGuidStorage.Get(doc, name, out named_guid, false); if (rc) { Util.InfoMsg(string.Format( "This document already has a project " + "identifier: {0} = {1}", name, named_guid.ToString())); rslt = Result.Succeeded; } else { rc = JtNamedGuidStorage.Get(doc, name, out named_guid, true); if (rc) { Util.InfoMsg(string.Format( "Created a new project identifier " + "for this document: {0} = {1}", name, named_guid.ToString())); rslt = Result.Succeeded; } else { Util.ErrorMsg("Something went wrong"); } } return(rslt); }