工作原理:

升级程序从服务器下载脚本文件，此文件中记载着最高版本号，经比较后，

可得知是否需要升级。然后弹出对话框，询问用户是否升级。若是，则按照升

级脚本中指定的地址下载新版本软件，并存放在本地特定目录下。下载完成后，

先让宿主程序退出，再将新文件覆盖旧文件。

若须自升级，则在升级程序退出时，生成临时批处理(bat)文件，EXE的自

删除和覆盖由批处理文件进行。

-How it works: Download the upgrade scr ipt file from the server, this file records the highest version number, by comparison, can know whether you need to upgrade. Then pop-up dialog box asking the user to upgrade. If so, then according to the address specified in the upgrade scr ipt to download the new version of the software, stored in a local-specific directory. After the download is complete, let the host quits, then the new file overwrites the old file. Since the upgrade, if required, then exit the upgrade process, generate temporary batch (bat) file, EXE self-delete and overwrite files from the batch.