1. 添加以下引用到 JS 文件
/// <reference path="file://C:/workspace/ExtJS4/ext-all-debug-w-comments.js" />
2.用VS快捷键 Ctrl + Shift + J ,更新intellisense
3.安装 Visual Assist X.
引用: http://www.sencha.com/forum/showthread.php?154630-Extjs-4-intellisense-in-visual-studio-2010