Cannot access protected member 'Foundation.NSDictionary.NSDictionary(System.IntPtr)' - ios

Question

We are trying to deploy our Xamarin built application to the Apple appstore and so we needed to migrate our application to the Unified Api to get 64-bit support. After upgrading to the latest version of Xamarin.iOS (Version: 8.8.2.4) and migrating the app to the Unified Api, we now get the following compile error:
Cannot access protected member 'Foundation.NSDictionary.NSDictionary(System.IntPtr)' via a qualifier of type 'Foundation.NSDictionary'.
The error occurs on this line:
NSDictionary prefSpecification = new NSDictionary(preferences.ValueAt(i));
of this method call:
public static void RegisterDefaultsFromSettingsBundle()
{
string settingsBundle = NSBundle.MainBundle.PathForResource("Settings", #"bundle");
if(settingsBundle == null) {
System.Console.WriteLine(#"Could not find Settings.bundle");
return;
}
NSString keyString = new NSString(#"Key");
NSString defaultString = new NSString(#"DefaultValue");
NSDictionary settings = NSDictionary.FromFile(Path.Combine(settingsBundle,#"Root.plist"));
NSArray preferences = (NSArray) settings.ValueForKey(new NSString(#"PreferenceSpecifiers"));
NSMutableDictionary defaultsToRegister = new NSMutableDictionary();
for (uint i=0; i<preferences.Count; i++) {
NSDictionary prefSpecification = new NSDictionary(preferences.ValueAt(i));
NSString key = (NSString) prefSpecification.ValueForKey(keyString);
if(key != null) {
NSObject def = prefSpecification.ValueForKey(defaultString);
if (def != null) {
defaultsToRegister.SetValueForKey(def, key);
}
}
}
NSUserDefaults.StandardUserDefaults.RegisterDefaults(defaultsToRegister);
}
Can anyone explain why this is happening and how I can work around this issue?

Answer 1

According to Apple docs, PreferenceSpecifiers is an Array of dictionaries, so instead of doing this:
NSDictionary prefSpecification = new NSDictionary(preferences.ValueAt(i));
You should be able to do this:
NSDictionary prefSpecification = (NSDictionary)preferences.ValueAt(i);
Udated
If you are using the new unified API, you will have to subclass the desired class (NSDictionary in this case) to have access to the NSDictionary(IntPtr) constructor as described on this Xamarin docs.
Hope it helps