Building a nav from the top level page of a structure

Question

There are several questions like this already but none seem to cover my use case. I have a structure that looks something like this:

Landing Page 1
- Case Studies
-- Case Study 1
-- Case Study 2
-- Case Study 3
- Sub page
- Sub page
Landing Page 2
- Case Studies
-- Case Study 1
-- Case Study 2
-- Case Study 3
- Sub page
- Sub page

If I'm in any child of the 'Landing Pages' I want to create a nav (as per the docs) but I cant' seem to get all of the pages I need. I can easily get the top level 'landing page':

entry.getAncestors().level(1).first()

I can then get the descendants separately:

entry.getAncestors().level(1).first().getDescendants()

However, I want a single ElementCriteriaModel with everything from the 'landing page' down in it.

Is this possible?

Answer 1

Untested, but you should be able to do this by using the merge filter in Twig to join the two results together.

Get the top level 'landing page' for this section:

{% set landingPage = entry.getAncestors().level(1) %}

Get the descendants for this section:

{% set childPages = entry.getAncestors().level(1).getDescendants() %}

Merge the two results together:

{% set sectionPages = [ landingPage ]|merge(childPages) %}

Now create the navigation for the section using the sectionPages variable:

<nav>
    <ul>
        {% nav page in sectionPages %}
            <li>
                {{ page.getLink() }}

                {% ifchildren %}
                    <ul>
                        {% children %}
                    </ul>
                {% endifchildren %}
            </li>
        {% endnav %}
    </ul>
</nav>

Answer 2

Basically the same as Steve suggested, but I first merged the entries' IDs and then use them as a criteria in another craft.entries call:

{% set landing = entry.getAncestors().level(1).first() %}

{% set landingId = landing.id %}
{% set ancestorIds = landing.getDescendants().ids() %}
{% set entryIds = [ landingId ]|merge( ancestorIds ) %}

{% set entries = craft.entries.id(entryIds) %}