title: Pass data from CollectionView Delegate to another ViewController
body: <p>I'm beginner on Swift.</p>
  
  <p>I have <code>CollectionView</code> in my <code>UIViewController</code> and I need to pass data when user clicks on <code>CollectionViewCell</code> to another <code>ViewController</code>.
  I tried to override <code>prepareForSegue</code> but I notice that it called first then code on <code>didSelectItemAtIndexPath</code>.</p>
  
  <p><strong>My First ViewController Code:</strong></p>
  
  <pre><code>import UIKit
  
  class ViewController: UIViewController {
  
      ...
  
      override func viewDidLoad() {
          super.viewDidLoad()
      }
  }
  
  extension ViewController : UICollectionViewDataSource,UICollectionViewDelegate{
  
      func numberOfSectionsInCollectionView(collectionView: UICollectionView) -&gt; Int {
          return 1
      }
  
      func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -&gt; Int {
          return items.count
      }
  
      func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -&gt; UICollectionViewCell {
          let cell = collectionView.dequeueReusableCellWithReuseIdentifier("collCell", forIndexPath: indexPath) as! MainCollectionViewCell
  
          ...
          return cell
      }
  
      func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
  
          itemId = items[indexPath.item].id
  
          let distinationViewController = DistinationViewController()
          distinationViewController.itemId = itemId
      }   
  }
  </code></pre>
  
  <p><strong>My Distination view controller code</strong></p>
  
  <pre><code>import UIKit
  
  class DistinationViewController: UIViewController{
  
      var itemId : String!
  
      override func viewDidLoad() {
          super.viewDidLoad()
          // Do any additional setup after loading the view.
          print(itemId)
      }
  }
  </code></pre>
  
  <p>The value of <code>itemId</code> in <code>DistinationViewController</code> is nil</p>
  
  <p>Thanks</p>