This documentation is deprecated since Admin Columns version 4.
Please view the updated version of this documentation here.

The filter cac/column/value can be used to alter what’s displayed in a column on the content (e.g. posts, users, comments) overview pages.

Usage

/**
 * Change the value before being displayed as a column value.
 *
 * @param string $value Value
 * @param int $object_id Post/User/Comment/Term ID
 * @param object $column CPAC_Column object
 * @return string $storage_key e.g.: post/page/wp-users/wp-media/wp-comments
 * @return string $value Column value
 */
function my_cac_action_change_column_value( $value, $object_id, $column, $storage_key ) {

    // Possibly modify $value

    return $value;
}
add_filter( 'cac/column/value', 'my_cac_action_change_column_value', 10, 4 ); // All columns for all content types

You can also target a specific storage model, such as user or post, using cac/column/value/{$storage_type} (where the storage type can be either post, taxonomy, media, comment or user): 
add_filter( 'cac/column/value/user', 'my_cac_action_change_column_value', 10, 4 ); // Columns on the user overview page
add_filter( 'cac/column/value/post', 'my_cac_action_change_column_value', 10, 4 ); // Columns on the post overview page
add_filter( 'cac/column/value/comment', 'my_cac_action_change_column_value', 10, 4 ); // Columns on the comment overview page
add_filter( 'cac/column/value/media', 'my_cac_action_change_column_value', 10, 4 ); // Columns on the media overview page
add_filter( 'cac/column/value/taxonomy', 'my_cac_action_change_column_value', 10, 4 ); // Columns on the taxonomy overview page

Examples

In the example below, we display text notifying the user that no image is available for empty featured image columns. 

/**
 * Display text notifying the user that no image is available
 *
 */
function my_change_column_featured_image_value( $value, $object_id, $column, $storage_key ) {

	if ( 'column-featured_image' === $column->get_type() && empty( $value ) ) {
		$value = '<em>' . __( 'No featured image', 'myplugin' ) . '</em>';
	}

	return $value;
}
add_filter( 'cac/column/value', 'my_change_column_featured_image_value', 10, 4 );