login.pas

一个用Delphi做的不错的学生宿舍管理系统！界面比前一个好看！

unit login;

interface

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

type
  TLoginForm = class(TForm)
    GroupBox: TGroupBox;
    Image1: TImage;
    Label1: TLabel;
    Label2: TLabel;
    ComboBox1: TComboBox;
    Edit1: TEdit;
    Panel1: TPanel;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    procedure ComboBox1DropDown(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  LoginForm: TLoginForm;

implementation
uses md,main;
{$R *.dfm}
var
itimes:integer=0;
procedure TLoginForm.ComboBox1DropDown(Sender: TObject);
var
i:integer;
begin
// 当用户选择已经存在的或用户可以输入数据
combobox1.Clear;
with datamd.ADOManage do
begin
  close;
  sql.Clear;
  sql.Add('select * from manage');
  open;
  if recordcount>0 then
  begin
    first;
    for i:=0 to recordcount-1 do
    begin
    combobox1.Items.Add(fieldbyname('用户名').AsString);
    next;
    end;
  end
  else
   showmessage('当前没有用户。请原谅'); //当前没有记录就不能对数据进行操作
end;
end;

procedure TLoginForm.BitBtn1Click(Sender: TObject);
var
password,username:string;
begin
username:=combobox1.Text; // 用户名
password:=edit1.Text; //密码
inc(itimes);
if combobox1.Items.Count>0 then
begin
   combobox1.ItemIndex:=0;
   with datamd.ADOManage do
     begin
       // 当用户名与密码正确并且输入次数少于三次时就登录成功
       if locate('用户名',username,[lopartialkey]) and locate('密码',password,[lopartialkey]) and (itimes<4) then
        begin
          close;
          sql.Clear;
          sql.Add('select * from manage where 用户名='''+username+''''+' and  密码='''+password+'''');
          open;
          application.CreateForm(TmainForm,mainform);
          mainform.StatusBar1.Panels.Items[1].Text:=username;
          mainform.StatusBar1.Panels.Items[3].Text:=fieldbyname('权限').AsString;
          if fieldbyname('权限').AsString='操作员' then
            begin
                with mainform do
                begin
                roomsetitem.Enabled:=false;
                roommanageitem.Enabled:=false;
                edwitem.Enabled:=false;
                Mdfyitem.Enabled:=false;
                adduitem.Enabled:=false;
                epitem.Enabled:=false;
                end
            end;
          loginform.Hide;
          loginform.Free;
          mainform.ShowModal;
          mainform.Free;
        end
       else
       begin
         if MessageDlg('密码密码，请重新输入',mtConfirmation, [mbYes, mbNo],0)=mrYes then
           begin
            edit1.Clear;
            edit1.SetFocus;
           end
           else
             close;
       end;
       if itimes>3 then
         begin
          showmessage('很抱歉。你没有权力使用本系统');
          application.Terminate;
         end;
     end;
end
else
 showmessage('数据库没有用户名');
end;

procedure TLoginForm.BitBtn2Click(Sender: TObject);
begin
application.Terminate;
end;

end.