C# UICollectionView类代码示例

        public override void ItemSelected(UICollectionView collectionView, NSIndexPath indexPath)
        {
            if (lastSelectedCell != null) {
                lastSelectedCell.BackgroundColor = UIColor.Clear;
            }

            var cell = collectionView.CellForItem (indexPath);
            cell.BackgroundColor = UIColor.Cyan;

            lastSelectedCell = cell;

            if (cell is FriendsPuzzleListCellViewController) {
            //				var friendsCell = cell as FriendsPuzzleListCellViewController;
            //				var puzzle = puzzlesWitHFriends [indexPath.Item - 1];

            } else if (cell is FriendsPuzzleListNewCellViewController) {

                var vc = this.Storyboard.InstantiateViewController("MenuCreateViewController") as MenuCreateViewController;
                vc.IsFriendMatch = true;

                NavigationController.PushViewController(
                    vc,
                    true
                    );
            }
        }

 public override int GetItemsCount(UICollectionView collectionView, int section)
 {
     if (section == 0)
         return Team1.Count;
     else
         return Team2.Count;
 }

        public override UICollectionViewCell GetCell(UICollectionView collectionView, Foundation.NSIndexPath indexPath)
        {
            var cell = (ListingImageCell)collectionView.DequeueReusableCell(CellID, indexPath);
            cell.Image = urls[indexPath.Row];

            return cell;
        }

 public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
 {
     var cell = collectionView.DequeueReusableCell(ToolCell.Key, indexPath) as ToolCell;
     cell.Text = AvailableTools[indexPath.Item].Name;
     cell.SetBorder();
     return cell;
 }

        public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
        {
            DBError err;
            PhotoCell cell = (PhotoCell)collectionView.DequeueReusableCell(PhotoCell.Key, indexPath);

            DBPath path = Photos [Photos.Length - indexPath.Row - 1].Path;
            DBFile file = DBFilesystem.SharedFilesystem.OpenFile (path, out err);
            UIImage image = null;

            // This means the file doesn't exist, or it is open with asynchronous operation.
            if (file == null) {
                cell.Content = null;
                return cell;
            }

            if (file.Status.Cached) {
                image = new UIImage (file.ReadData (out err));
                file.Close ();
            } else {
                file.AddObserver (this, () => {
                    DBFileStatus newStatus = file.NewerStatus;

                    if ((newStatus == null && file.Status.Cached) ||
                        (newStatus != null && newStatus.Cached)) {
                        image = new UIImage (file.ReadData (out err));
                        cell.Content = image;
                        file.RemoveObserver(this);
                        file.Close ();
                    }
                });
            }
            cell.Content = image;

            return cell;
        }

		public override void MoveItem (UICollectionView collectionView, NSIndexPath sourceIndexPath, NSIndexPath destinationIndexPath)
		{
			// Reorder our list of items
			var item = Numbers [(int)sourceIndexPath.Item];
			Numbers.RemoveAt ((int)sourceIndexPath.Item);
			Numbers.Insert ((int)destinationIndexPath.Item, item);
		}

 public override nint GetItemsCount(UICollectionView collectionView, nint section)
 {
     if ((dateList == null) || (dateList.Count == 0))
         return (nint)0;
     else
         return (nint)dateList.Count;
 }

		public override CoreGraphics.CGSize GetSizeForItem (UICollectionView collectionView, UICollectionViewLayout layout, Foundation.NSIndexPath indexPath)
		{
			if (Master.MaxHeight != 0) {
				return new CoreGraphics.CGSize ((Master.View.Frame.Size.Width - 10) / 3, Master.MaxHeight);
			}
			return new CoreGraphics.CGSize ((Master.View.Frame.Size.Width - padding - 10) / 3, (Master.View.Frame.Size.Width - padding - 10) / 3 + differential);
		}

        public override UICollectionReusableView GetViewForSupplementaryElement(UICollectionView collectionView, NSString elementKind, NSIndexPath indexPath)
        {
            if (elementKind == (NSString)"UICollectionElementKindSectionHeader") {
                PictureHeaderVIew header = (PictureHeaderVIew)collectionView.DequeueReusableSupplementaryView
                    (UICollectionElementKindSection.Header, (NSString)"header", indexPath);
                header.title.Frame = new RectangleF (20, 15, 230, 300);
                header.title.Text = Items.Title;
                header.title.Lines = 0;
                header.title.SizeToFit ();
                header.photo.Image = UIImage.FromFile ("./Assets/photo.png");
                header.picturesCount.Text = Items.Images.Count.ToString();

                return header;
            }
            else {
                StartReadingView footer = (StartReadingView)collectionView.DequeueReusableSupplementaryView
                    (UICollectionElementKindSection.Footer, (NSString)"collectionfooter", indexPath);
                footer.StartReading.SetBackgroundImage (UIImage.FromFile ("./Assets/buttonlong.png"), UIControlState.Normal);
                footer.StartReading.TouchUpInside += (object sender, EventArgs e) => {
                    UIStoryboard board = UIStoryboard.FromName ("MainStoryboard", null);
                    var prefs = (PreferencesSubController)board.InstantiateViewController ("preferencessub");
                    this.NavigationController.PushViewController(prefs, true);
                };
                return footer;
            }
        }

		public override UICollectionViewCell GetCell (UICollectionView collectionView, NSIndexPath indexPath)
		{
			var cell = (ProductCell)collectionView.DequeueReusableCell (reuseIdentifier, indexPath);
			ConfigureCell (cell, Products [indexPath.Row]);

			return cell;
		}

		public override nint NumberOfSections (UICollectionView collectionView)
		{
			if (Master.CollectionItems == null || Master.CollectionItems.Count == 0) {
				return 0;
			}
			return 1;
		}

		public override int GetItemsCount (UICollectionView collectionView, int section)
		{
			if (ItemsSource == null)
				return 0;
			
			return ItemsSource.Count();
		}

 public override void ItemSelected(UICollectionView collectionView, NSIndexPath indexPath)
 {
     var photoController = new PhotoViewController {
         Asset = (PHAsset)fetchResults[indexPath.Item]
     };
     NavigationController.PushViewController (photoController, true);
 }

 public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
 {
     var cell = (PictureBigCollectionCell)collectionView.DequeueReusableCell (PictureBigCollectionCell.CellId, indexPath);
     cell.resetScale ();
     AppDelegate.MakeImageFromURL (cell.Image, Items.Images [indexPath.Row]);
     return cell;
 }

		// TODO: Step 2c: uncomment to get a header instance to use for the Supplementary View
		public override UICollectionReusableView GetViewForSupplementaryElement (UICollectionView collectionView, NSString elementKind, NSIndexPath indexPath)
		{
			// get a Header instance to use for the supplementary view
			var headerView = (Header)collectionView.DequeueReusableSupplementaryView (elementKind, headerId, indexPath);
			headerView.Text = "Evolve Speakers";
			return headerView;
		}