对自定义XML文件的读、写、修改、删除操作，加入简单类工厂和单例模式，便于扩展。打包成DLL，EX为测试项-XML documents to read, write, modify, delete operations, adding a simple type of plant and single-case model, convenient for extension. Packaged into a DLL, EX test items

XML文件管理,可以对XML文件进行各种操作,包括插入,删除,修改,更新等-XML Manager

压缩包内是一个用WPF写的通讯录，没有数据库操作，所有数据保存在xml文件中。-Compressed within a book written with WPF, there is no database operation, all data stored in the xml file.