1。如果您正在开发winform，请阅读： sample-c -windows-form-login-screen [ ^ ]

2.如果您正在开发asp.net，请阅读：会员资格介绍 [ ^ ]

1. If you are developing winform, read this: sample-c-windows-form-login-screen[^]
2. If you are developing asp.net, read this: Introduction to Membership[^]

使用3 db tables.one用于用户详细信息，其中一个列字段将是用户组ID。第二个表将用于存储针对组ID的用户凭证。第三个将用于组名和组ID。



登录时首先识别用户（组），如果识别出用户，则获取他的组ID并验证它来自用户详细信息表。然后从凭证表中检查该组ID是否有效密码。

Use 3 db tables.one is for user details in which one of the column field will be user group id . 2nd table will be for storing user credentials against group id. & third one will be for group name & group id.

During log in first identify the user(group),if identified user then get his group id & validate it from user details table. & then check that group id for valid password from credentials table.