unitlogin.~pas

这个代码虽然还没有 全部写完

unit UnitLogin;

interface

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

type
  TFormLogin = class(TForm)
    LabelUser: TLabel;
    EditPasswd: TEdit;
    LabelPasswd: TLabel;
    LabelPlease: TLabel;
    BitBtnOK: TBitBtn;
    BitBtnCancel: TBitBtn;
    EditUser: TEdit;
    Table1: TTable;
    Database1: TDatabase;
    procedure BitBtnOKClick(Sender: TObject);
    procedure BitBtnCancelClick(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  //登录验证窗口
  FormLogin: TFormLogin;
  //应用程序退出标志
  AppExitFlag: Boolean;

implementation

{$R *.dfm}

//响应窗口显示事件
procedure TFormLogin.FormShow(Sender: TObject);
begin
  //设置应用程序退出标志为True
  AppExitFlag:=True;
end;

//响应窗口关闭事件
procedure TFormLogin.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  //如果应用程序退出标志为Ture，即没有通过用户验证，则中止该应用程序
  if AppExitFlag=true then
     //中止该应用程序
     Application.Terminate();
end;

//响应"确定"按钮
procedure TFormLogin.BitBtnOKClick(Sender: TObject);
begin
  //在User表的关键字(即Name列)中查找是否存在该用户
  if Table1.FindKey([EditUser.text])=false then
    //显示提示信息
    MessageBox(Handle,'该用户不存在，请重新输入。','提示',MB_OK OR MB_ICONINFORMATION)
  else
    //判断该用户的密码是否正确
    if Table1.FieldValues['Passwd']=EditPasswd.Text then
    begin
      //设置应用程序退出标志为False
      AppExitFlag:=False;
      //关闭登录验证框
      FormLogin.Close();
    end
    else
      //显示提示信息
      MessageBox(Handle,'密码不正确，请重新输入。','提示',MB_OK OR MB_ICONINFORMATION);
end;

//响应"取消"按钮
procedure TFormLogin.BitBtnCancelClick(Sender: TObject);
begin
  //关闭该表
  Table1.Close();
  //关闭登录验证框
  FormLogin.Close();
end;    

end.