This quick tip explains how to add a Custom Column in the Manage Screens of your WordPress blog.

Here are some code snippets you can use to customize the columns in your Manage Screens.

You can copy and paste them into your theme's functions.php file, or download the plugin attached to this post.

Step 1 Define Column Functions

First, let's define some helper functions that we will hook into WordPress later. The first two add the new column (or two columns, or remove a default one), while the others display the column content. In these examples we assume that you have already activated a movie Custom Post Type and a genre Custom Taxonomy. You can read about creating custom post types and taxonomies in a previous article.

function ST4_columns_head($defaults) {
	$defaults['first_column']  = 'First Column';

	/* ADD ANOTHER COLUMN (OPTIONAL) */
	// $defaults['second_column'] = 'Second Column';

	/* REMOVE DEFAULT CATEGORY COLUMN (OPTIONAL) */
	// unset($defaults['categories']);

	/* TO GET DEFAULTS COLUMN NAMES: */
	// print_r($defaults);

	return $defaults;
}

// ONLY FOR movie CUSTOM POST TYPE
function ST4_columns_head_movies($defaults) {
	$defaults['my_movie_column'] = 'MY MOVIE COLUMN';
	return $defaults;
}

// GENERAL PURPOSE
function ST4_columns_content($column_name, $post_ID) {
	if ($column_name == 'first_column') {
		// DO STUFF FOR first_column COLUMN
		echo 'The post ID is: ' . $post_ID;
	}

	/* IF YOU NEED ANOTHER COLUMN - UNCOMMENT ALSO
	$defaults['second_column'] = 'Second Column';
	in ST4_columns_head()
	*/

	/*
	if ($column_name == 'second_column') {
		// DO STUFF FOR second_column COLUMN
	}
	*/
}

// TAXONOMIES: CATEGORIES (POSTS AND LINKS), TAGS AND CUSTOM TAXONOMIES
function ST4_columns_content_taxonomy($c, $column_name, $term_id) {
	if ($column_name == 'first_column') {
		echo 'The term ID is: ' . $term_id;
	}
}

// USERS
function ST4_columns_content_users($c, $column_name, $user_id) {
	if ($column_name == 'first_column') {
		$output .=  'The user ID is: ' . $user_id;
	}
	if ($column_name == 'second_column') {
		$output .=  'This is the second column content';
	}
	return $output;
}

// CUSTOM POSTS
function ST4_columns_content_movies($column_name, $movie_ID) {
	if ($column_name == 'my_movie_column') {
		echo 'The movie ID is: ' . $movie_ID;
	}
}

Step 2 Hook the Column Functions to WordPress

Now, let's hook the functions into WordPress Manage Screens:

Posts and Post Types, Except Pages

add_filter('manage_posts_columns', 'ST4_columns_head');
add_filter('manage_posts_custom_column', 'ST4_columns_content', 10, 2);

Only WordPress Default Posts

add_filter('manage_post_posts_columns', 'ST4_columns_head', 10);
add_action('manage_post_posts_custom_column', 'ST4_columns_content', 10, 2);

Only WordPress Default Pages

add_filter('manage_page_posts_columns', 'ST4_columns_head', 10);
add_action('manage_page_posts_custom_column', 'ST4_columns_content', 10, 2);

Only Movie Custom Post Type

add_filter('manage_movie_posts_columns', 'ST4_columns_head_movies', 10);
add_action('manage_movie_posts_custom_column', 'ST4_columns_content_movies', 10, 2);

Post Categories

add_filter('manage_edit-category_columns', 'ST4_columns_head');
add_filter('manage_category_custom_column', 'ST4_columns_content_taxonomy', 10, 2);

Only Genre Custom Taxonomy

add_filter('manage_edit-genre_columns', 'ST4_columns_head');
add_filter('manage_genre_custom_column', 'ST4_columns_content_taxonomy', 10, 2);

Post Tags

add_filter('manage_edit-post_tag_columns', 'ST4_columns_head');
add_filter('manage_post_tag_custom_column', 'ST4_columns_content_taxonomy', 10, 2);

Link Categories

add_filter('manage_edit-link_category_columns', 'ST4_columns_head');
add_filter('manage_link_category_custom_column', 'ST4_columns_content_taxonomy', 10, 2);

Media Library

add_filter('manage_media_columns', 'ST4_columns_head');
add_filter('manage_media_custom_column', 'ST4_columns_content', 10, 2);

Users

add_filter('manage_users_columns', 'ST4_columns_head');
add_filter('manage_users_custom_column', 'ST4_columns_content_users', 10, 2);

Final Notes

Two final notes: if a Manage Screen has no items, for example there are no Tags yet, the content of the new column is not displayed.

The ST4_columns_content_users function it's slightly different from the others, since it returns a PHP variable containing the HTML, instead of printing the column content on the fly.