login.pas

蛮不错的图书管理系统,大家可以载着试试看啊

unit login;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Buttons, ExtCtrls, jpeg,dbtables,global, DB;

type
  Tloginfrm = class(TForm)
    Image1: TImage;
    Panel1: TPanel;
    Label1: TLabel;
    Label2: TLabel;
    edit1: TEdit;
    edit2: TEdit;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    Table1: TTable;
    DataSource1: TDataSource;
    q1: TQuery;
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
  private
    { Private declarations }
  function checkuser(username,no:string):integer ;
  public
    { Public declarations }
  end;

var
  loginfrm: Tloginfrm;

implementation
     uses  main1,gl ;
{$R *.dfm}

function Tloginfrm.checkuser(username,no:string):integer;
  var t:TTable;
  begin
       t:=Table1;
      try
       t.Open;
       t.SetKey;
       t.FieldByName('图书卡号').AsString:=username;
       if not(t.GotoKey) then
          begin

             MessageDlg('图书卡号'+username+'错误!',mtError,[mbok],0);
             Result:=-1;
             Exit;
          end
       else
          if t.FieldByName('密码').AsString=no then
             Result:=t.FieldByName('等级').AsInteger
          else
             begin
                MessageDlg('密码错误!',mtError,[mbok],0);
                Result:=-1;
                Exit;
             end;
        except
        Result:=-1;
        MessageDlg('连接数据库出错',mtError,[mbok],0);
      end;
end;


procedure Tloginfrm.BitBtn2Click(Sender: TObject);
begin
close;
end;

procedure Tloginfrm.FormShow(Sender: TObject);
begin
      edit1.clear;
      edit2.clear;
      edit1.setfocus;

     
end;



procedure Tloginfrm.BitBtn1Click(Sender: TObject);
  var rs1:integer;
      cardno,passw:string;
begin
      
      if trim(edit1.text)=''then
         begin
           messagedlg('请输入图书卡号!',mtinformation,[mbyes],0);
           edit1.clear;
           edit2.clear;
           edit1.setfocus;
           exit;
         end;
      q1.SQL.Clear;
      q1.SQL.Add('select * from student_info where 图书卡号=:n');
      q1.ParamByName('n').AsString:=edit1.Text;
      q1.Open;
      username:=q1.FieldByName('姓名').AsString;
      userno:=edit1.Text;
      cardno:=edit1.text;
      passw:=edit2.text;
      rs1:=checkuser(cardno,passw);
      if rs1<>-1 then  begin
                       loginfrm.Visible:=false;
                       main.Visible:=true;
                       main.viewmenu(rs1);
                       end

      else
       begin
         edit2.clear;
         edit1.setfocus;
         exit;
         end;
    close;
   end;
end.