One select search for Users in user.group

Question

I'm a complete newby on Craft CMS and twig templating so please bear with me.

I currently have a users base which I want to filter by category (a custom field)

This would be my only input search element:

<select name="professionalita">
    <option value="" disabled selected>Professionalità</option>
    {% for category in craft.categories.group('professionalita') %}
    <option value="{{category.url}}">{{ category.title }}</option>
    {% endfor %}
</select>

This is what I tried to build on results.html page.

{# Get the search data #}
{% set profParam = craft.request.getParam('professionalita') %}

{% extends "_inc/layout" %}

{% block main %}
    {# Find and list matching entries #}
    {% set members = craft.users.group.('members').relatedTo(profParam) %}

    {% if members|length %}
        <ul>
            {% for member in members %}
                <li>{{ member.firstName }}</li>
            {% endfor %}
        </ul>
    {% else %}
        No members found.
    {% endif %}
{% endblock %}

I get no results even if there are actually correspondencies between the users and the category name being searched for.

Answer 1

I suggest you to read the docs about relations. You can search for relations by the following parameter

In its simplest form, you can pass in one of these things to it:

An AssetFileModel, CategoryModel, EntryModel, UserModel, or TagModel object

An element’s ID

An array of element objects and/or IDs

What you pass is a string or to be more specific a url

<option value="{{category.url}}">{{ category.title }}</option>

What you have to do is:

<option value="{{category.id}}">{{ category.title }}</option>

In order to find users related to a category id.

However I strongly suggest you to build your search with PHP if you are going to include multiple parameters (more categories/search terms/complex and+or bindings) it is going to be a mess with twig