login.pas

我觉得是很好的一个程序是关于房产中介的管理系统包跨哦出租出售求租求售的

unit login;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Buttons, ExtCtrls, Db, DBClient, ADODB, ComCtrls;

type
  TFrm_Login = class(TForm)
    bbtnok: TBitBtn;
    btncancel: TBitBtn;
    GroupBox2: TGroupBox;
    cbUserId: TComboBox;
    Label3: TLabel;
    Label4: TLabel;
    edtPassword: TEdit;
    ADOQ_Temp: TADOQuery;
    procedure btncancelClick(Sender: TObject);
    procedure bbtnokClick(Sender: TObject);
    procedure edtPasswordKeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure FormCreate(Sender: TObject);
    procedure edituseridKeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormShow(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    login:boolean;
  end;

var
  Frm_Login: TFrm_Login;
  LoginNum  :integer;

implementation

uses DataBase, Common;



{$R *.DFM}

procedure TFrm_Login.btncancelClick(Sender: TObject);
begin
  Login :=False;
  close;
end;

procedure TFrm_Login.bbtnokClick(Sender: TObject);
begin
  //录入检验
  if cbUserId.text='' then
  begin
    messagedlg('请 选 择 用 户 名 ！',mtInformation,[mbok],0);
    cbUserId.SetFocus();
    exit;
  end;

  //登录验证
  with ADOQ_Temp do
  begin
    close;
    SQL.Clear;
    SQL.Add('SELECT * From 用户信息表 Where 用户名='+''''+cbUserId.Text+'''');
    Open;
    //用户有效性
    IF not IsEmpty then
    begin
      //登录失败
      If edtPassword.Text <> Fieldbyname('密码').AsString then
      begin
      	messagedlg('口令错误，请修改 ！',mterror,[mbok],0);
       	LoginNum:=LoginNum+1;
	      if LoginNum=3 then
        begin
     	    messagedlg('非法用户！你无权使用本系统',mterror,[mbok],0);
          application.Terminate ;
        end;
        edtPassword.Text :='';
        edtPassword.SetFocus;
        exit;
      end
      //登录成功
      else
      begin
        //保存登录的用户信息
        gs_login_userid     :=fieldbyname('用户名').asstring;
        gs_login_username   :=fieldbyname('用户名').asstring;
        gs_login_userlevel  :=fieldbyname('用户等级').asstring;
        gs_login_Password   :=fieldbyname('密码').asstring;
        gt_login_time:=now();

        Login:=true;
        self.close;
      end;
    end
    else
    begin
      messagedlg('指定的用户已被注销！你无权使用本系统！',mterror,[mbok],0);
      Login:=False;
      self.close;
    end;
  end;
end;

procedure TFrm_Login.edtPasswordKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if key=VK_RETURN then
     bbtnOk.SetFocus ;
end;

procedure TFrm_Login.FormCreate(Sender: TObject);
begin
  //
  Login:=false;

  // 初始化用户选择列表
  with ADOQ_Temp do
  begin
    close;
    SQL.Clear;
    SQL.Add('SELECT 用户名 From 用户信息表');
    Open;
    while not eof do
    begin
      cbUserId.Items.Add(FieldByName('用户名').AsString);
      Next;
    end;
    close;
  end;
  cbUserId.ItemIndex:= 0;

end;

procedure TFrm_Login.edituseridKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if key=VK_RETURN then
    edtPassword.SetFocus;
end;

procedure TFrm_Login.FormClose(Sender: TObject; var Action: TCloseAction);
begin
//
end;


procedure TFrm_Login.FormShow(Sender: TObject);
begin
  //
  edtPassword.SetFocus();
  
end;

end.