untdl.~pas

这是一个Delphi很好很全面知识的实例

unit untDL;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, jpeg, ExtCtrls, Buttons;

type
  TfrmDL = class(TForm)
    Panel1: TPanel;
    GroupBox1: TGroupBox;
    GroupBox3: TGroupBox;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    GroupBox2: TGroupBox;
    Image1: TImage;
    Label1: TLabel;
    Label2: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure Edit1KeyPress(Sender: TObject; var Key: Char);
    procedure Edit2KeyPress(Sender: TObject; var Key: Char);
  private
    { Private declarations }
  public
    { Public declarations }
    loginsuccessed:boolean;{ 定义两个公共变量}
    isadmin:boolean;
  end;

var
  frmDL: TfrmDL;

implementation

uses MDUnit1, mainUnit1, ZCBBUnit1, SRBBUnit1, ZCDYUnit1, SRDYUnit1;

{$R *.dfm}

procedure TfrmDL.BitBtn1Click(Sender: TObject);//确定
begin
if (edit1.text='')or(edit2.Text='') then
     begin
      messagedlg('请正确填写姓名和密码！',mtwarning,[mbok],0);
      edit1.SetFocus;
     end 
else
  begin
    md.ADOMMQuery3.Close;
    md.ADOMMQuery3.SQL.Clear;
    md.ADOMMQuery3.SQL.Add('select * from 密码表');
    md.ADOMMQuery3.SQL.Add('where 用户名=:user_name and 密码=:pass');
    md.ADOMMQuery3.Parameters.ParamByName('user_name').Value:=edit1.Text;
    md.ADOMMQuery3.Parameters.ParamByName('pass').Value:=edit2.Text;
    md.ADOMMQuery3.Open;
    if md.ADOMMQuery3.RecordCount >=1 then
    begin
      if md.ADOMMQuery3.FieldByName('权限').Value<>'0' then
         mainform.xt.Enabled:=false;
         isadmin:=true;  //具有系统管理员权限
         loginsuccessed:=true;
         mainform.StatusBar1.Panels[1].Text:='操作人员：'+Edit1.Text;
         close; //关闭登陆窗体，进入主窗体
      end
      else
        messagedlg('没有此用户或密码错误，请重新登陆！',mtwarning,[mbok],0);
        edit1.clear;//让EDIT1清空
        edit2.Clear;
        edit1.SetFocus;
      end;
end;


procedure TfrmDL.BitBtn2Click(Sender: TObject); //退出
begin
  if messagedlg('您真的要离开吗？',mtinformation,[mbyes,mbno],0)=mryes then
   application.Terminate
  else
   Abort;
end;

procedure TfrmDL.FormShow(Sender: TObject);
begin
   srbbform.Hide;// 让 srbbform、zcbbform、srdyform、zcdyform隐藏
   zcbbform.Hide;
   srdyform.Hide;
   zcdyform.Hide;
   edit1.SetFocus;//让eidt1获取焦点
   edit1.Height:=25;
   edit2.Height:=25;
end;
procedure TfrmDL.FormClose(Sender: TObject; var Action: TCloseAction);
begin
if not loginsuccessed then
     application.Terminate;
end;

procedure TfrmDL.Edit1KeyPress(Sender: TObject; var Key: Char);//击回车键让光标移动到eidt2中
begin
  if key=#13 then
  edit2.SetFocus;
end;

procedure TfrmDL.Edit2KeyPress(Sender: TObject; var Key: Char);//击回车键处发bitbtn1的click事件，进入系统
begin
  if key=#13 then
    begin
      bitbtn1.SetFocus;
      bitbtn1click(sender);
    end;
end;

end.