活动桌面的问题

代码如下：uses shlobj,comobj; function SetActiveDesktop(const b: Boolean): integer;
var
Desktop: IActiveDesktop;
Info: TComponentsOpt;
begin
DeskTop := CreateComObject(CLSID_ActiveDesktop) as IActiveDesktop;
Result := GetLastError;
info.dwSize := sizeof(info);
info.fActiveDesktop := b;
info.fEnableComponents := false;
Desktop.SetDesktopItemOptions(info, 0);
DeskTop.ApplyChanges(AD_APPLY_ALL);
end;function SetActiveDesktopWallpaper(FileName: string): integer;
var
Desktop: IActiveDesktop;
Temp: WideString;
begin
DeskTop := CreateComObject(CLSID_ActiveDesktop) as IActiveDesktop;
Result := GetLastError;
Temp := FileName;
Desktop.SetWallpaper(PWideChar(Temp), 0);
DeskTop.ApplyChanges(AD_APPLY_ALL);
end;IActiveDesktop应该是一个接口，还有TComponentsOpt，不知道在哪定义的？