Store token locally in Xamarin.IOS - xamarin.ios

Question

I am working on a Xamarin cross-platform native project and I have to store the token (get from the server after login) both Android and IOS side. On the Android side I used SharedPreferences which works great, but I can't find a solution for IOS. Now I am using KeyChain, but the result is always wrong.
Here is my code:
The KeyChain class:
using System;
using Foundation;
using Security;
namespace BloodNotes.iOS
{
public class KeyChain
{
public string ValueForKey(string key)
{
var record = ExistingRecordForKey(key);
SecStatusCode resultCode;
var match = SecKeyChain.QueryAsRecord(record, out resultCode);
if (resultCode == SecStatusCode.Success)
return NSString.FromData(match.ValueData, NSStringEncoding.UTF8);
else
return String.Empty;
}
public void SetValueForKey(string value, string key)
{
var record = ExistingRecordForKey(key);
if (value == "")
{
if (ValueForKey(key) != "")
RemoveRecord(record);
return;
}
// if the key already exists, remove it
if (ValueForKey(key) != "")
RemoveRecord(record);
var result = SecKeyChain.Add(CreateRecordForNewKeyValue(key, value));
if (result != SecStatusCode.Success)
{
throw new Exception(String.Format("Error adding record: " + result)); // I ALWAYS GET THIS EXCEPTION
}
}
private SecRecord CreateRecordForNewKeyValue(string key, string value)
{
return new SecRecord(SecKind.GenericPassword)
{
Account = key,
ValueData = NSData.FromString(value, NSStringEncoding.UTF8),
};
}
private SecRecord ExistingRecordForKey(string key)
{
return new SecRecord(SecKind.GenericPassword)
{
Account = key,
Label = key,
};
}
private bool RemoveRecord(SecRecord record)
{
var result = SecKeyChain.Remove(record);
if (result != SecStatusCode.Success)
{
throw new Exception(String.Format("Error removing record: {0}", result));
}
return true;
}
}
}
And the TokenService:
using BloodNotes.ViewModel;
using Foundation;
using System.Diagnostics;
namespace BloodNotes.iOS.TokenService
{
class TokenService : Service.ITokenService
{
public const string KEY = "token";
public void SaveToken(string token)
{
KeyChain storage = new KeyChain();
storage.SetValueForKey(token, KEY);
Debug.WriteLine("RESULT: " + storage.ValueForKey(KEY));
}
}
}
Please, give me advise.
Thanks in advance for the answers!

Answer 1

Finally, I found a solution. Instead of KeyChain use NSUserDefaults.StandardUserDefaults, so my TokenService looks like:
using Foundation;
using System.Diagnostics;
namespace BloodNotes.iOS.TokenService
{
class TokenService : Service.ITokenService
{
public const string KEY = "token";
public void SaveToken(string token)
{
var storage = NSUserDefaults.StandardUserDefaults;
NSString value = new NSString(token);
NSString key = new NSString(KEY);
storage.SetValueForKey(value, key);
Debug.WriteLine("RESULT: " + storage.ValueForKey(key).ToString());
}
}
}