C#登录窗体实现与权限验证教程

你ACCESS里添加个权限的列。然后SQL语句
“select * from [表名]”最后判断不同的权限 进入不同的窗体。我代码发你吧。
 sql = @"Data Source=PC-19800104AFVX;Persist Security Info=True;User ID=sa;Password=123";
            con = new SqlConnection(sql);
            string loginSql = "select * from [user] where user_id='"+this.txtID.Text+"' and user_pwd='"+this.txtPwd.Text+"'";
            con.Open();
            com = new SqlCommand(loginSql,con);
            if (txtID.Text == "" || txtPwd.Text == "")
            {
                MessageBox.Show("请输入账号密码！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                txtID.Focus();
                txtID.SelectAll();
                txtPwd.Clear();
            }
            else
            {
                myreader = com.ExecuteReader();
                if (!myreader.Read())
                {
                    MessageBox.Show("用户名或密码错误！");
                }
                else
                {
                    this.label_now.Text = myreader[2].ToString();
                    //MessageBox.Show("欢迎" + this.label_syte.Text + "：" + txtID.Text + "登录");
                    if (this.label_now.Text == "管理员用户")
                    {
                        string p = this.txtID.Text;
                        Form_gly frm_gly = new Form_gly(p);
                        frm_gly.Show();