copy sheet revit api

public void CopySheet()
{
    Document doc = this.ActiveUIDocument.Document;

    ViewSheet activeViewSheet = doc.ActiveView as ViewSheet;
    if (activeViewSheet == null)
    {
        TaskDialog.Show("Error", "Active view must be a sheet.");
        return;
    }

    Application app = this.Application;
    Document otherDoc = app.Documents.Cast<Document>().Where(d => d.Title != doc.Title).FirstOrDefault();
    if (otherDoc == null)
    {
        TaskDialog.Show("Error", "There must be a 2nd document open.");
        return;
    }

    // put the sheet in the source document into the copyIds collection
       ICollection<ElementId> copyIds = new Collection<ElementId>();
    copyIds.Add(activeViewSheet.Id);    

    // put view-specific elements on the sheet in the copyIdsViewSpecific collection
    ICollection<ElementId> copyIdsViewSpecific = new Collection<ElementId>();
    foreach (Element e in new FilteredElementCollector(doc).OwnedByView(doc.ActiveView.Id))
    {
        // do not put viewports into this collection because they cannot be copied
        if (!(e is Viewport))
            copyIdsViewSpecific.Add(e.Id);    
    }

    // Create a transaction in the source document to delete the viewports.
    // This transaction will be rolled-back so it won't cause any permanent change in the document
    // but it will enable copying of the sheet while it is in a state with no viewports
    using (Transaction t = new Transaction(doc,"Delete Viewports"))
    {
        t.Start();

        IList<Viewport> viewports = new FilteredElementCollector(doc).OfClass(typeof(Viewport)).Cast<Viewport>()
            .Where(q => q.SheetId == activeViewSheet.Id).ToList();

        foreach (Viewport vp in viewports)
        {
            doc.Delete(vp.Id);
        }

        using (Transaction tOther = new Transaction(otherDoc, "Copy View Template"))
        {
            tOther.Start();
            // copy the sheet using the CopyElements overload that accepts source and destination documents
            // get the newly created sheet in the target document - it will be the first (and only) element returned by ElementTransformUtils.CopyElements
            ViewSheet newSheet = otherDoc.GetElement(ElementTransformUtils.CopyElements(doc, copyIds, otherDoc, Transform.Identity, new CopyPasteOptions()).First()) as ViewSheet;

            // copy the view-specific elements using the CopyElements overload that accepts source and destination views
            ElementTransformUtils.CopyElements(activeViewSheet, copyIdsViewSpecific, newSheet, Transform.Identity, new CopyPasteOptions());

            tOther.Commit();
        }

        // rollback the transaction to "undo" the deletion of the viewports
        t.RollBack();
    }
}