Custom Pagination for WPMU Marketpress

code.php

<?php

add_filter( 'mp_products_nav', 'mp_products_nav_cb', 99, 2 );
function mp_products_nav_cb( $html, $custom_query ){
	
	
	global $wp_query, $mp;

	$args = $mp->parse_args(func_get_args(), $mp->defaults['list_products']);
	$args['nopaging'] = false;

	$query = array(
		'post_type' => 'product',
		'post_status' => 'publish',
	);
	$tax_query = array();

	//setup taxonomies if possible
	if ( $wp_query->get('taxonomy') == 'product_category' ) {
		$tax_query[] = array(
			'taxonomy' => 'product_category',
			'field' => 'slug',
			'terms' => $wp_query->get('term'),
		);
	} elseif ( $wp_query->get('taxonomy') == 'product_tag' ) {
		$tax_query[] = array(
			'taxonomy' => 'product_tag',
			'field' => 'slug',
			'terms' => $wp_query->get('term'),
		);
	} elseif ( !is_null($args['category']) || !is_null($args['tag']) ) {
		if ( !is_null($args['category']) ) {
			$tax_query[] = array(
				'taxonomy' => 'product_category',
				'field' => 'slug',
				'terms' => sanitize_title($args['category']),
			);
		}

		if ( !is_null($args['tag']) ) {
			$tax_query[] = array(
				'taxonomy' => 'product_tag',
				'field' => 'slug',
				'terms' => sanitize_title($args['tag']),
			);
		}
	}

	if ( count($tax_query) > 1 ) {
		$query['tax_query'] = array_merge(array('relation' => 'AND'), $tax_query);
	} elseif ( count($tax_query) == 1 ) {
		$query['tax_query'] = $tax_query;
	}

	//setup pagination
	if ( (!is_null($args['paginate']) && !$args['paginate']) || (is_null($args['paginate']) && !$mp->get_setting('paginate')) ) {
		$query['nopaging'] = $args['nopaging'] = true;
	} else {
		//figure out perpage
		$query['posts_per_page'] = -1;

		//figure out page
		if ( !is_null($args['page']) ) {
			$query['paged'] = intval($args['page']);
		} elseif ( $wp_query->get('paged') != '' ) {
			$query['paged'] = $args['page'] = intval($wp_query->get('paged'));
		}

		//get order by
		if ( is_null($args['order_by']) ) {
			if ( 'price' == $mp->get_setting('order_by') ) {
				$query['meta_key'] = 'mp_price_sort';
				$query['orderby'] = 'meta_value_num';
			} elseif ( 'sales' == $mp->get_setting('order_by') ) {
				$query['meta_key'] = 'mp_sales_count';
				$query['orderby'] = 'meta_value_num';
			} else {
				$query['orderby'] = $mp->get_setting('order_by');
			}
		} else {
			if ( 'price' == $args['order_by'] ) {
				$query['meta_key'] = 'mp_price_sort';
				$query['orderby'] = 'meta_value_num';
			} else if ( 'sales' == $args['order_by'] ) {
				$query['meta_key'] = 'mp_sales_count';
				$query['orderby'] = 'meta_value_num';
			} else {
				$query['orderby'] = $args['order_by'];
			}
		}
	}

	//get order direction
	if ( is_null($args['order']) ) {
		$query['order'] = $mp->get_setting('order');
	} else {
		$query['order'] = $args['order'];
	}

	//The Query
	$my_query = new WP_Query($query);
	$tot = count($my_query->posts);
	
	$page = max(1, $custom_query->get('paged'));
	$max = $custom_query->max_num_pages;
	$prev=$next=$html=$mid='';
	$flag = 3;

	if ($max > 1) {
		if ($page != 1) {
			$html.='<a href="#page='.($page-1).'">'.__('Prev').'</a>';
		}

		$j = 0;
		$dot = 0;
		$a = $b = 0;
		for( $i = 0; $i < $tot; $i += $mp->get_setting('per_page') ){
			if( $j < $flag ){
				$html.=  '<a ' . ( $page == $j+1 ? 'class="activePage"' : '' ) . ' href="#page='.(++$j).'">'.$j.'</a>';
			}elseif( $tot > $j && $j >= ( ( $tot / $mp->get_setting('per_page') ) - $flag ) ){
				$html.=  '<a ' . ( $page == $j+1 ? 'class="activePage"' : '' ) . ' href="#page='.(++$j).'">'.$j.'</a>';
			}
			else{
				if( ($page - 2) <= $j && $j <= ($page) ){
					$html.=  '<a ' . ( $page == $j+1 ? 'class="activePage"' : '' ) . ' href="#page='.(++$j).'">'.$j.'</a>';
				}else{
					if( $j > $flag ){
						if( $a++ == 0 )
							$html .= '...';
					}
					if( $j > ( $page + 2 ) ){
						if( $b++ == 0 )
							$html .= '...';
					}
					$j++;
				}
			}
			
			
		}
		$i = $j = 0;

		if ( $page != $max ) {
			$html.='<a href="#page='.($page+1).'">'.__('Next').'</a>';
		}

		$html = '<div id="mp_product_nav">' . $html . '</div>';
	}
	
	return $html;
}

You can add those codes in your functions.php in the theme, if you think your theme won’t be changed. Otherwise mu-plugins is the best solution. To use mu-plugins, go to /wp-content/ and find the folder with name 'mu-plugins'. If there is no folder in that name, then create a folder, name it 'mu-plugins', create a file inside that, give any name you like and paste the code in there. You don't need to activate that plugin. Mu-plugins means must use plugins, so it will be activated automatically always. If you use mu-plugins then add a php start tag at the beginning of the code.