ulogin.pas

《Delphi通用模块及典型系统开发实例导航》配套光盘第一章（记录文件）

unit uLogin;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, InvokeRegistry, StdCtrls, DB, DBClient, ExtCtrls;

const
  conFileName = 'user.info';
    
type
  PUserRec = ^TUserRec;
  TUserRec = record
    UserName: string[12];
    Password: string[12];
  end;  

  TLoginDlg = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    edtPassword: TEdit;
    edtAccount: TEdit;
    Panel1: TPanel;
    btnOK: TButton;
    btnCancel: TButton;
    procedure btnOKClick(Sender: TObject);
  private
  public
    class function Execute: Boolean; 
    function VerifyAccount: Boolean;
  end;

implementation


{$R *.dfm}
{ TLoginDlg }
class function TLoginDlg.Execute: Boolean;
begin
  with TLoginDlg.Create(nil) do
  try
    Result := ShowModal = mrOk;
  finally
    Free;
  end;
end;

function TLoginDlg.VerifyAccount: Boolean;
var
  F: file of TUserRec;
  UserRec: TUserRec;
  i: Integer;
begin
  Result := False;
  AssignFile(F, conFileName);
  Reset(F);
  for i := 0 to FileSize(F)-1 do
  begin
    Read(F, UserRec);
    if (UserRec.UserName = edtAccount.Text) and (UserRec.Password = edtPassword.Text) then
    begin
      ModalResult := mrOK;
      Break;
    end;
  end;
  CloseFile(F);
  Result := ModalResult = mrOk;
end;

procedure TLoginDlg.btnOKClick(Sender: TObject);
begin
  if not VerifyAccount then ShowMessage('帐号或密码错误，请重新输入!');
end;

end.