title: UIPickerView is not populated with data fetched from CoreData
body: <p>So here is my problem. I am trying to fetch values from CoreData, my data tables have data in them thus I do not see why this occurs. When I open the view hosting the UIPickerView there is not data present. </p>
  
  <p>Below is my code.</p>
  
  <p>ViewController header:</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  
   @interface EBPaymentViewController : UIViewController &lt;UIPickerViewDelegate&gt;
  
   @property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
   @property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
   @property (readonly, strong, nonatomic) NSPersistentStoreCoordinator    *persistentStoreCoordinator;
  
  @property (nonatomic, strong) NSMutableArray *voucherTypes;
  @property (weak, nonatomic) IBOutlet UIPickerView *voucherTypePicker;
  
  @end
  </code></pre>
  
  <p>Below here is my viewDidLoad</p>
  
  <pre><code>- (void)viewDidLoad
  {
       [super viewDidLoad];
       // Do any additional setup after loading the view.
  
       // load the data from the database and populate the UIPickerView.
       EBAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
       _managedObjectContext = [appDelegate managedObjectContext];
  
       NSFetchRequest *request = [[NSFetchRequest alloc] init];
       NSEntityDescription *vouchers
           = [NSEntityDescription entityForName:@"VoucherTypes"     inManagedObjectContext:_managedObjectContext];
  
      [request setEntity:vouchers];
  
       NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:@"voucherType" ascending:YES];
       NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:descriptor, nil];
       [request setSortDescriptors:sortDescriptors];
  
       NSError *error = nil;
       NSMutableArray *mutableFetchResults = [[_managedObjectContext   executeFetchRequest:request error:&amp;error] mutableCopy];
  
      if(mutableFetchResults == nil)
      {
      // handle error
      }
  
      [self setVoucherTypes:mutableFetchResults];
  
  }
  </code></pre>
  
  <p>And finally my titleForRow:</p>
  
  <pre><code>- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row   forComponent:(NSInteger)component
  {
      return [voucherTypes objectAtIndex:row];
  }
  </code></pre>
  
  <p>The UIPickerView is just empty. Any help would be appreciated!</p>