title: Unable to pass value back to parentViewController
body: <p>I have masterViewController and detailViewController. Masterview pushes detailView. When going back to masteViewController I want to update the foo value. But I only get NULL from nslog. How can I set the parenteViewContrller.foo value to @"bar" when navigationback?  </p>
  
  <p>masterViewController.h</p>
  
  <pre><code>    NSString *foo; 
      -(void)setFoo:(NSString *)fooValue
      @property(nonatomic, retain) NSString *foo; 
  </code></pre>
  
  <p>masterViewController.m</p>
  
  <pre><code>@synthesize foo;
  
  -(void)setFoo:(NSString *)fooValue{
  
      NSLog(@"updated foo:%@", fooValue);
  }
  </code></pre>
  
  <p>detailViewController.m</p>
  
  <pre><code>-(void)goBack{
      [self.navigationController.parentViewController setValue:@"bar" forKey:@"foo"];
      [self.navigationController popViewControllerAnimated:YES];
  }
  </code></pre>