unit1.pas

精彩编程百例75～100 其中有媒体播放器 SQL语言编辑器 ADO方法连接多个数据库 用户密码验证系统 获取Man地址 信史服务 ping命令等待

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Label2: TLabel;
    Label3: TLabel;
    Table1: TTable;
    Ok1: TBitBtn;
    Exit1: TBitBtn;
    procedure FormCreate(Sender: TObject);
    procedure Ok1Click(Sender: TObject);
    procedure Exit1Click(Sender: TObject);
    procedure Edit2KeyPress(Sender: TObject;
    var Key: Char);

  private

    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  count:integer;

implementation

{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
begin
  count:=0 //Count初始值为0
end;

procedure TForm1.Ok1Click(Sender: TObject);
var
  results:variant;
  i:integer;
begin
  table1.Active:=true;//窗体初始化时，连接数据库
  count:=count+1;{计数加1}
  i:=count;
  results:=table1.Lookup('name',edit1.text,'password');{检索数据库中对应用户名的密码项}
  if results=edit2.Text then
    showmessage('密码确认，即将进入银行用户信息系统。'){如果对应相同则进入，此处只是示例，所以只是简单说明密码确认}
  else
  begin
    showmessage('错误的用户名或密码！您还有'+inttostr(3-i)+'次机会');{密码不确认}
      if (count=3) then
      close;{三次输入错误，退出}
  end;

end;

procedure TForm1.Exit1Click(Sender: TObject);
begin
  close; //关闭窗体，退出程序
end;

procedure TForm1.Edit2KeyPress(Sender: TObject; var Key: Char);
begin
  if (key=#13) then //当在Edit2中输入密码后，按回车键，执行密码检查
    ok1.Click
  else
end;

end.