login.pas

图书管理系统DELPHI版本

unit login;

interface

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

type
  Tloginfrm = class(TForm)
    GroupBox1: TGroupBox;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    Image1: TImage;
    Label1: TLabel;
    Label2: TLabel;
    namebox: TEdit;
    pwdbox: TEdit;
    procedure BitBtn2Click(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
  private
    { Private declarations }
  function checkuser(ausername,apwd:string):integer;
  public
    { Public declarations }
  end;

var
  loginfrm: Tloginfrm;

implementation
   uses global,main;
{$R *.dfm}

//----------验证用户身份----------//
function Tloginfrm.checkuser(ausername,apwd:string):integer;
var t:TTable;
begin
  try
    t := TTable.Create(nil);
    t.DatabaseName :=DBName;
    t.tablename:='user_info.db';
    t.Open;
    t.setkey;
    t.FieldByName('姓名').AsString:=ausername;
    if not(t.gotokey) then
      begin
        MessageDlg('用户名'+ausername+'错误!',mtError,[mbok],0);
        Result := -1;
        Exit;
      end
    else
      if t.fieldbyname('学生证号').asstring=apwd then
         Result := t.FieldByName('等级').AsInteger
      else
        begin
        MessageDlg('密码错误!',mtError,[mbok],0);
        Result := -1;
        Exit;
        end;
    t.Close;
    t.Free;
  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.BitBtn1Click(Sender: TObject);
var rsl:integer;
begin
if trim(namebox.Text)='' then
  begin
  messagedlg('没有用户名，请输入！',mtinformation,[mbYes],0);
  namebox.Clear ;
  pwdbox.Clear ;
  namebox.SetFocus ;
  exit;
  end;
username :=namebox.Text ;
userpwd :=pwdbox.Text ;
rsl:=checkuser(username,userpwd);
if rsl<>-1 then mainfrm.viewmenu(rsl)
else
  begin
  pwdbox.Clear ;
  namebox.SetFocus ;
  exit;
  end;
close;
end;

procedure Tloginfrm.FormShow(Sender: TObject);
begin
namebox.Clear ;
pwdbox.Clear ;
namebox.SetFocus ;
end;

end.