难道这些代码在2000下无效？？？？？？？

Question

我因为无聊，所以写个定时更新墙纸的小东东，
可网上广为流传的两种方式都没用，至少不能立即更新。下面贴出代码，希望大家指正：1：
procedure setwallpaper(fileName:String);
var
  Reg:Tregistry;
begin
  Reg:=Tregistry.Create;
  Reg.RootKey:=HKey_Current_User;
  Reg.OpenKey('Control Panel\Desktop',False);
  Reg.WriteString('TileWallPaper','0');//改为('TileWallPaper','1')平铺
  Reg.WriteString('WallPaper',fileName);
  SystemParametersInfo(SPI_SETDESKWALLPAPER,0,nil,SPIF_SendChange);
  Reg.CloseKey;
  Reg.Free;
end;2:
procedure setwallpaper(fileName:String);
begin
  {调用API函数SystemParametersInfo来设置桌面墙纸的图片文件为'c:\windows\mywallpaper.bmp'}
  SystemParametersInfo(SPI_SETDESKWALLPAPER, 0,Pchar(fileName), SPIF_UPDATEINIFILE);
end;

Answer 1

SystemParametersInfo这个函数在2000下是无效的，只能在9x下才有用

Answer 2

uses
  ShlObj, ComObj;
function ChangeWallpaper(aFile: String): Boolean;
const
  CLSID_ActiveDesktop: TGUID = '{75048700-EF1F-11D0-9888-006097DEACF9}';
var
  hObj: IUnknown;
  ADesktop: IActiveDesktop;
  str: string;
  wstr: PWideChar;
begin
  hObj     := CreateComObject(CLSID_ActiveDesktop);
  ADesktop := hObj as IActiveDesktop;
  wstr := AllocMem(MAX_PATH);
  try
    StringToWideChar(aFile, wstr, MAX_PATH);
    ADesktop.SetWallpaper(wstr, 0);
    ADesktop.ApplyChanges(AD_APPLY_ALL or AD_APPLY_FORCE);
  finally
    FreeMem(wstr);
  end;
end;

Answer 3

太好了，非常感谢aiirii(ari-爱的眼睛)