dismiss viewController by using presentingViewController - ios

Question

I have three ViewControllers and its order is (A present B which presents C),
when I stay in the C viewController ,I have to dismiss ViewController to B viewController.
for C viewController ,its presentingViewCOntroller is B viewController
of course ,I can use
[self dismissViewControllerAnimated:YES completion:NULL];//self means C ViewController
But I was wondering I can also use the following method:
[self.presentingViewController dismissViewControllerAnimated:YES completion:NULL];
because the presentingViewController of C is B ViewController, but it did the same effect.
self means C ViewController while self.presentingViewController means B ViewController,but they also did the same work
The second question is I cannot use the following to dismiss two viewController in succession:
[self dismissViewControllerAnimated:YES completion:^{
[self.presentingViewController.presentingViewController dismissViewControllerAnimated:YES completion:NULL];
}]; //self means C viewController
Thanks for your help!

Answer 1

of course ,I can use
[self dismissViewControllerAnimated:YES completion:NULL];//self means C ViewController
This only dismisses C, not B as you seem to want.
But I was wondering I can also use the following method:
[self.presentingViewController.presentingViewController dismissViewControllerAnimated:YES completion:NULL];
Yes, this works. When in doubt, try it out.
The second question is I cannot use the following to dismiss two viewController in succession:
[self dismissViewControllerAnimated:YES completion:^{
[self.presentingViewController.presentingViewController dismissViewControllerAnimated:YES completion:NULL];
}]; //self means C viewController
That's not a question. Anyway, the reason it doesn't work is that after you dismiss yourself, your presentingViewController is nil. You need to store it in a temporary variable.
UIViewController *gp = self.presentingViewController.presentingViewController;
[self dismissViewControllerAnimated:YES completion:^{
[gp dismissViewControllerAnimated:YES completion:nil];
[self.presentingViewController.presentingViewController dismissViewControllerAnimated:YES completion:nil];
}];
Of course, the two will have different animations, you'll need to decide which you prefer.

Answer 2

see documentation:
The presenting view controller is responsible for dismissing the view
controller it presented. If you call this method on the presented view
controller itself, it automatically forwards the message to the
presenting view controller.

Answer 3

Please check: self.presentingViewController.presentingViewController is A viewController or not.
if not, I think you need use delegate or handler.
In my case, I used a tabbarcontroller as a rootViewController. When I used self.presentingViewController.presentingViewController, I got rootViewController (tabbarcontroller) which it have no response to presentingViewControler method.