How do I get navigation bar height for iOS?

I managed to get the Status Bar height using the following code. I placed the code in AppDelegate.cs and it works. It returns 20pt as expected.

App.StatusBarHeight = (string)UIApplication.SharedApplication.StatusBarFrame.Height.ToString ();

Now I am trying to get the navigation bar height. I could not figure out how to do. It should probably return a value of 44pt. I think it should look something like this

UINavigationController.NavigationBar.Bounds.Height

but thats not a valid code.

Any idea how I can get the navigation bar height?