Column headers & actions

A dynamic column often is a domain object — here every PropertyDefinition becomes a column whose <th> carries a link (via header:) and its own bulk action (via header_actions:). The action is declared on: :selection, so it submits the same shared select-form the toolbar's bulk actions use: tick a few rows, hit Tag in a column, and the checked selected[] reach that column's endpoint — acting on the ticked rows × that column's object. Declaring a :selection header action is what makes the table selectable (the checkboxes appear) — no extra wiring. header: replaces only the human_name; the same options work on a declared attribute too, not just a DynamicColumn.

@columns = PropertyDefinition.order(:id).map do |defn|
  CrudComponents::DynamicColumn.new(defn.key.to_sym,
    label:  defn.label,
    header: -> { link_to defn.label, columns_path(anchor: defn.key) },   # replaces only the human_name
    header_actions: [
      # acts on the TICKED rows × this column (defn); submits the shared select-form
      CrudComponents::Action.new(:tag_selected, on: :selection, icon: 'tag', method: :post) do
        tag_column_headers_path(key: defn.key)
      end
    ],
    preload: ->(records) { defn.values_by_subject(Book, records) }
  ) { |record, loaded| defn.cast(loaded[record.id]&.value) }
end

def tag                                       # the :selection header action's target
  books = CrudComponents.selected(Book, params)   # resolves the ticked selected[] slugs
  redirect_to column_headers_path,
              notice: "Tagged #{books.count} book(s) for '#{params[:key]}'…"
end

Read more: Custom headers & column actions  ·  Dynamic columns