Save a Set of Elements with SelectionFilterElement

Here’s another great question from a reader! Is it possible to save a selection, with a name, and call upon it later?

Yes, it is.

public void SelectionFilter()
{
    Document doc = this.ActiveUIDocument.Document;
    UIDocument uidoc = new UIDocument(doc);

    // Prompt user to pick one or more elements
    IList<Reference> refList = uidoc.Selection.PickObjects(ObjectType.Element, "Pick elements to add to selection filter");

    // Create a transaction
    using (Transaction t = new Transaction(doc,"Create & Add To Selection Filter"))
    {
        t.Start(); // Start the transaction

        // Create a SelectionFilterElement
        SelectionFilterElement selFilter = SelectionFilterElement.Create(doc,"My Selection Filter");

        foreach (Reference r in refList) // Iterate through list of selected elements
        {
            // Add the ElementId of each selected element to the selection filter
            selFilter.AddSingle(r.ElementId);
        }

        // Commit the transaction
        t.Commit();
    }
}

After the filter is created it can be seen in the Filters dialog. It cannot be applied to a view but it can be used in other ways which is a a good topic for a future posts.

P.S. If you try to run this macro twice, it will fail the 2nd time because the filter names must be unique. The IsNameUnique method could be used to check for this case.