c#连接数据库,，并建立用户验证系统。这个是用户验证系统，我其它的在C#中向数据库中添加数据，修改数据，不过在其它我上传的文件中！！

c# connects to the database, and establishes a user authentication system. This is the user authentication system. I have added data to the database in C# and modified the data, but in other files I uploaded! !