use-list-view-for-categories.php

/**
 * Redirect event category requests to list view.
 *
 * @param $query
 */
function use_list_view_for_categories( $query ) {
	// Disregard anything except a main archive query
	if ( is_admin() || ! $query->is_main_query() || ! is_archive() ) return;

	// We only want to catch *event* category requests being issued
	// against something other than list view
	if ( ! $query->get( 'tribe_events_cat' ) ) return;
	if ( tribe_is_list_view() ) return;

	// Get the term object
	$term = get_term_by( 'slug', $query->get( 'tribe_events_cat' ), TribeEvents::TAXONOMY );

	// If it's invalid don't go any further
	if ( ! $term ) return;

	// Get the list-view taxonomy link and redirect to it
	header( 'Location: ' . tribe_get_listview_link( $term->term_id ) );
	exit();
}

// Use list view for category requests by hooking into pre_get_posts for event queries
add_action( 'tribe_events_pre_get_posts', 'use_list_view_for_categories' );