A HitchHackers guide through WordPress

Source code

function choose_primary_blog() {

	?>

	<table class="form-table">

	<tr>

	<?php /* translators: My sites label */ ?>

		<th scope="row"><?php _e( 'Primary Site' ); ?></th>

		<td>

		<?php

		$all_blogs = get_blogs_of_user( get_current_user_id() );

		$primary_blog = get_user_meta( get_current_user_id(), 'primary_blog', true );

		if ( count( $all_blogs ) > 1 ) {

			$found = false;

			?>

			<select name="primary_blog">

				<?php foreach( (array) $all_blogs as $blog ) {

					if ( $primary_blog == $blog->userblog_id )

						$found = true;

					?><option value="<?php echo $blog->userblog_id ?>"<?php selected( $primary_blog,  $blog->userblog_id ); ?>><?php echo esc_url( get_home_url( $blog->userblog_id ) ) ?></option><?php

				} ?>

			</select>

			<?php

			if ( !$found ) {

				$blog = array_shift( $all_blogs );

				update_user_meta( get_current_user_id(), 'primary_blog', $blog->userblog_id );

			}

		} elseif ( count( $all_blogs ) == 1 ) {

			$blog = array_shift( $all_blogs );

			echo $blog->domain;

			if ( $primary_blog != $blog->userblog_id ) // Set the primary blog again if it's out of sync with blog list.

				update_user_meta( get_current_user_id(), 'primary_blog', $blog->userblog_id );

		} else {

			echo "N/A";

		}

		?>

		</td>

	</tr>

	<?php if ( in_array( get_site_option( 'registration' ), array( 'all', 'blog' ) ) ) : ?>

		<tr>

			<th scope="row" colspan="2" class="th-full">

				<a href="<?php echo apply_filters( 'wp_signup_location', network_home_url( 'wp-signup.php' ) ); ?>"><?php _e( 'Create a New Site' ); ?></a>

			</th>

		</tr>

	<?php endif; ?>

	</table>

	<?php

}