怎么显示另一个ViewController？？

在解散一个ViewController之后怎么显示另一个ViewController？
我的代码没实现，不知道在哪儿有错误

- (void)matchmakerViewControllerWasCancelled:
(GKMatchmakerViewController *)viewController{

    [self dismissModalViewControllerAnimated:YES];

   ViewController *Vc = [[ViewController alloc]init];
    [self presentModalViewController:Vc animated:YES];



}

如果在ModalViewController之后写NSLog，就会显示NSLog ，但是没有显示ViewController

[self dismissModalViewControllerAnimated:YES];

这句有问题；

试试这个：

- (void)matchmakerViewControllerWasCancelled:
(GKMatchmakerViewController *)viewController{

    [self dismissViewControllerAnimated:YES completion:^{
         ViewController *Vc = [[ViewController alloc]init];
         [self presentViewController:Vc animated:YES completion:^{}];
    }];
}