u_login.pas

教务管理系统,实现学生成绩管理,成绩查询,统计平均分最高分,学生选课,教务处安排教室,考试

unit U_login;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DBTables, DB, Grids, DBGrids, StdCtrls;

type
  TForm_login = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    edit_user: TEdit;
    edit_passwd: TEdit;
    Btn_login: TButton;
    btn_cancel: TButton;
    Query1: TQuery;
    Database1: TDatabase;
    procedure Btn_loginClick(Sender: TObject);
    procedure btn_cancelClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form_login: TForm_login;

implementation

uses U_main;

{$R *.dfm}

procedure TForm_login.Btn_loginClick(Sender: TObject);
begin
try
  database1.Connected:=True;                 //打开数据库连接
  query1.close;
  query1.ParamByName('id').Value:=edit_user.Text; //给query组件参数赋值
  query1.Open;                                    //用 query组件查询记录
  Except
  Application.MessageBox('请与系统管理员联系。','数据库连接错误！',mb_ok);
  Application.Terminate;                         //数据库连接错误，中断程序
  end;
if query1.Fields[0].value=null then					//没有检索出密码
begin
Application.MessageBox('请确认用户名是否正确！','用户名错误！',mb_ok);
exit;
end;
if query1.Fields[0].value=edit_passwd.Text then
begin
if  query1.Fields[1].value='2' then
begin
Form_login.hide;
form_main.show;
end
else
Application.MessageBox('请选择合适的登录软件！','用户权限错误！',mb_ok);
end
else
Application.MessageBox('密码不正确，注意大小写！','密码错误！',mb_ok);
end ;

procedure TForm_login.btn_cancelClick(Sender: TObject);
begin
close;
end;

procedure TForm_login.FormCreate(Sender: TObject);
begin
edit_user.Text:='';
edit_passwd.Text:='';
end;

end.