Question

I have a rootcontroller pushed on a UINavigationController.
Inside that rootcontroller class, I can access the UINavigationController with this.NavigationController

However, this rootcontroller has a ScrollView and I’m adding subcontrollers (or more precise, the View of this subcontroller) to this ScrollView.

I would now like to access the UINavigationController from inside such subcontroller.
Following properties are all null

        this.NavigationController
        this.ParentViewController
        this.PresentedViewController
        this.PresentingViewController

It seems in ObjectiveC you can use following code

YourAppDelegate *del = (YourAppDelegate *)[UIApplication sharedApplication].delegate;
[del.navigationController pushViewController:nextViewController animated:YES];

Unfortunately, i don’t know how to map this to C# in MonoTouch.
I tried the following, but it’s not working:

UIApplication.SharedApplication.KeyWindow.RootViewController.NavigationController

I know I could pass the UINavigationController object to all my classes (parameter in constructor), but that’s probably not the cleanest way to go.

Answer 1

To extend poupou’s answer, here is an example of what I usually do in my AppDelegate class:

Add a static property of the AppDelegate itself:

public static AppDelegate Self { get; private set; }

Add my root navigation controller as a property:

public UINavigationController MainNavController { get; private set; }

In FinishedLaunching:

Self = this;
window = new UIWindow(UIScreen.MainScreen.Bounds);
this.MainNavController = new UINavigationController(); // pass the nav controller's root controller in the constructor
window.RootViewController = this.MainNavController;
// ..

This way, I can access the root view controller from anywhere, like this:

AppDelegate.Self.MainNavController.PushViewController(someViewController);

… instead of having to write this all the time:

AppDelegate myAppDelegate = (AppDelegate)UIApplication.SharedApplication.Delegate;
myAppDelegate.MainNavController.PushViewController(someViewController);

Plus, I can directly access all other AppDelegate‘s properties I might have.

Hope this helps.