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（数据库存储）

unit uLogin;

interface

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

type
  TLoginDlg = class(TForm)
    adocUser: TADOConnection;
    adoqUser: TADOQuery;
    ImageBackground: TImage;
    Image4: TImage;
    Image5: TImage;
    edtPassword: TEdit;
    RadioButtonSeller: TRadioButton;
    RadioButtonAdmin: TRadioButton;
    edtAccount: TEdit;
    btnOK: TButton;
    btnCancel: TButton;
    Image3: TImage;
    Image2: TImage;
    procedure btnOKClick(Sender: TObject);
    procedure Image4Click(Sender: TObject);
    procedure Image3Click(Sender: TObject);
    procedure Image2Click(Sender: TObject);
  private
  public
    //验证帐号匹配，具体实现应不同的存储方式而不同，将在以下各实现细节中说明
    function VerifyAccount: Boolean;
    //一个类方法，以便在Project主程序中调用此方法来执行登录，
    //如果登录成功返回True，否阿返回False。
    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;
begin
  Result := False;
  with adoqUser do
  begin
    Parameters.ParamByName('UserName').Value := edtAccount.Text;
    Parameters.ParamByName('Password').Value := edtPassword.Text;
    if Active then Close;
    Open;
    if RecordCount > 0 then ModalResult := mrOk;
  end;
  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;

procedure TLoginDlg.Image4Click(Sender: TObject);
begin
if not VerifyAccount then ShowMessage('帐号或密码错误，请重新输入!');
end;

procedure TLoginDlg.Image3Click(Sender: TObject);
begin
application.Minimize;
end;

procedure TLoginDlg.Image2Click(Sender: TObject);
begin
application.Terminate;
end;

end.