检查操作系统下是否安装了net.framework,以及它的版本号-Check whether the installed operating system net.framework, as well as its version number

图书管理系统1:安装.NET Framework可以运行程序，安装VS.NET可以修改源程序和运行程序。 2：安装SQL SERVER2000，附加data文件夹下的数据库。 运行“代码\bin”文件夹下的exe文件，程序运行。-Library management system 1: Install. NET Framework to run programs, install VS.NET can modify the source code and run the progr

基于.NET的三层架够工厂模式代码,包含加密工具,数据库-Based. NET framework enough to plant three-tier model code, including encryption tools, database