Add new file

class-user-autocomplete.php

+<?php 
+
+/**
+ * Classe per Admin Wordpress
+ */
+
+class UserAutoComplete {
+    
+    public function __construct(){
+        add_action( 'admin_enqueue_scripts', array(&$this, 'add_scripts'));
+        add_action( 'wp_ajax_user_search', array(&$this, 'user_search') ); 
+    }
+    
+
+    public function user_search(){
+    	$term = strtolower( $_REQUEST['term'] );
+    	$suggestions = array();
+    	
+    	$user_query = new WP_User_Query( array(
+    			'search'         => '*'. $_REQUEST['term'] .'*',
+    			'search_columns' => array( 'user_login', 'user_email', 'user_nicename' )
+    	) );
+    	
+    	if ( ! empty( $user_query->get_results() ) ) {
+    		foreach ( $user_query->get_results() as $user ) {
+    			
+    			$suggestion = array();
+    			$suggestion['label'] = $user->display_name;
+    			$suggestion['email'] = $user->user_email;
+    			$suggestion['value'] = $user->ID;
+    			$suggestions[] = $suggestion;
+    		}
+    	} 
+    	
+    	wp_reset_query();
+    	
+    	
+    	$response = json_encode( $suggestions );
+    	echo $response;
+    	exit();
+    	
+    }
+    
+    public function add_scripts(){
+    	wp_enqueue_script( 'jquery' );
+    	wp_enqueue_script( 'jquery-ui-autocomplete' );
+	}
+	
+	public function print_form_autocomplete(){
+		?>
+			<form id="user-filter" method="get">
+				<label>Filtra per nome <input id="user-search" type="text" style="width:300px" value=""/></label>
+				<input type="hidden" id="user-id" name="user_id" />
+				<input type="submit" class="button-primary" value="Cerca"/>
+			</form>
+
+			<script>
+			jQuery(document).ready(function($) {
+
+				var url = ajaxurl + "?action=user_search";
+
+				$( "#user-search" ).autocomplete({
+					source: url,
+					delay: 500,
+					minLength: 3,
+					focus: function( event, ui ) {
+						$( "#user-search" ).val( ui.item.label );
+						return false;
+						},
+					select: function( event, ui ) {
+						console.log ('selezionato ', ui);
+						$( "#user-search" ).val( ui.item.label );
+						$('#user-id').val(ui.item.value);
+						return false;
+					}
+				})
+				.autocomplete( "instance" )._renderItem = function( ul, item ) {
+						return $( "<li>" )
+						.append( "<div>" + item.label + " - <small style='color:#999'>" + item.email + "</small></div>" )
+						.appendTo( ul );
+					};
+			
+			
+			});
+			</script>
+		<?php
+	}
+
+
+    
+}
+