iOS導航欄跳轉

iOS中當註冊的根視圖中的導航欄還不存在的時候，想要用導航欄跳轉 

RegristerChooseController * rgc=[UIStoryboardViewControllerInStoryBoard:@"RegristerChooseController"withIdentified:@"RegristerChooseController"];

    rgc.hidesBottomBarWhenPushed=YES;

    UINavigationController *nv =[[UINavigationControlleralloc] initWithRootViewController:rgc];

    [selfpresentViewController:nv animated:YEScompletion:nil];

    [self.navigationControllerpushViewController:rgc animated:YES];