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（文本文件）

unit uLogin;

interface

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

type
  TLoginDlg = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    edtPassword: TEdit;
    cdsUserList: TClientDataSet;
    edtAccount: TEdit;
    Panel1: TPanel;
    btnOK: TButton;
    btnCancel: TButton;
    procedure btnOKClick(Sender: TObject);
  private
  public
    function VerifyAccount: Boolean;
    class function Execute: 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
  TextFileVar: TextFile;
  sUserName, sPassword, sLine: string;
begin
  Result := False;
  AssignFile(TextFileVar, 'user.txt');
  Reset(TextFileVar);
  while not Eof(TextFileVar) do
  begin
    ReadLn(TextFileVar, sLine);
    sUserName := Copy(sLine, 0, Pos('=', sLine)-1);
    sPassword := Copy(sLine, Pos('=', sLine)+1, MaxInt);
    //帐号不区分大小写，密码区分大小写
    if SameText(sUserName, edtAccount.Text) and (sPassword = edtPassword.Text) then
    begin
      ModalResult := mrOk;
      Break;
    end;
  end;
  CloseFile(TextFileVar);
  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.