UICollectionview单元格中的SDWebImage会干扰滚动

Question

我有一个UICollectionView，其中包含有图像的单元格。这些图像是从网址下载的。问题是每当我滚动UICollectionView时，都会重新加载单元格，并且单元格中会出现重复的图像几秒钟。

这完全扰乱了细胞。以下是我的一些代码

var pictureCollectionSource = new PictureCollectionSource(picRefined);
  pictureCollection.Source = pictureCollectionSource;
  picturecollectiondelegate = new PictureCollectionViewDelegate(picRefined);
  pictureCollection.Delegate = picturecollectiondelegate;

PictureCollectionViewDelegate.cs

public class PictureCollectionViewDelegate : UICollectionViewDelegateFlowLayout
    {
        public delegate void CellClickedEvent(object sender, EventArgs e);
        public event CellClickedEvent CellClicked;
        private IEnumerable<ProfileValues> picRefined;

        public PictureCollectionViewDelegate(IEnumerable<ProfileValues> picRefined)
        {
            // TODO: Complete member initialization
            this.picRefined = picRefined;
        }

        public override CoreGraphics.CGSize GetSizeForItem(UICollectionView collectionView, UICollectionViewLayout layout, Foundation.NSIndexPath indexPath)
        {

                var width = (UIScreen.MainScreen.Bounds.Size.Width / 4);
               return new CoreGraphics.CGSize(width, width);

        }
    }

PictureCollectionSource.cs

public override UICollectionViewCell GetCell(UICollectionView collectionView, Foundation.NSIndexPath indexPath)
        {
            var cell = collectionView.DequeueReusableCell (cell_id, indexPath) as PictureCollectionCell ?? PictureCollectionCell.Create();

            var data = picRefined.ElementAt(indexPath.Row);

            cell.UpdateCell(data);
            return cell;
        }

UpdateCell

internal void UpdateCell(ProfileValues mdata)
        {


            var mUrl = "someurl";

   var manager = SDWebImageManager.SharedManager;
   manager.ImageCache.MaxCacheAge = 86400;
            SDWebImageDownloader mDownloader = manager.ImageDownloader;

            var authToken = "SomeToken"";


            mDownloader.SetHttpHeaderValue(authToken, "Authorization");
            mDownloader.SetHttpHeaderValue("application/json; odata=verbose", "Accept");
            mDownloader.SetHttpHeaderValue("f", "X-FORMS_BASED_AUTH_ACCEPTED");


            try
            {
                mDownloader.DownloadImage(
                 url: new NSUrl(mUrl),
     options: SDWebImageDownloaderOptions.ProgressiveDownload,
                progressBlock: (receivedSize, expectedSize) =>
                {
                    // Track progress...
                },
                completedBlock: (image, data, error, finished) =>
                {

                    if (image != null && finished)
                    {
                        InvokeOnMainThread(() =>
                        {

                            this.imgProfilePic.Image = image;
                        });

                    }
                    if (error != null)
                    {
                        InvokeOnMainThread(() =>
                        {
                            this.imgProfilePic.Image = errorImage;
                            this.imgProfilePic.BackgroundColor = UIColor.FromRGB(52, 31, 71);
                            //this.imgProfilePic.Layer.CornerRadius = this.imgProfilePic.Frame.Size.Width / 2;
                            this.imgProfilePic.ClipsToBounds = true;
                            this.imgProfilePic.Layer.BorderWidth = 3.0f;
                            this.imgProfilePic.Layer.BorderColor = UIColor.White.CGColor;
                        });
                    }
                }


              );
            }
            catch (Exception ex)
            {
            }
        }

修改

我尝试使用评论中建议的静态单元格。我在故事板UICollectionView中添加了16个单元格。修改了我的UICollectionVIewSource，如下所示： -

List<string> cellIds = new List<string>(){"pic_collection_cell","cell_2","cell_3","cell_4","cell_5","cell_6"
    ,"cell_7","cell_8","cell_9","cell_10","cell_11","cell_12","cell_13","cell_14","cell_15","cell_16"};

 public override UICollectionViewCell GetCell (UICollectionView collectionView, Foundation.NSIndexPath indexPath)
  {
   int cellIndex = (int)indexPath.Item;

   if (cellIndex >= cellIds.Count) {
    cellIndex = 0;
   }

   UICollectionViewCell cell = collectionView.DequeueReusableCell (cellIds [cellIndex], indexPath) as UICollectionViewCell;

    profImage = new UIImageView (cell.Frame);
    profImage.Image = UIImage.FromFile ("ic_account.png");

    cell.AddSubview (profImage);


            return cell;
        }

但有了这个，即使调试器显示将imageview添加到其他单元格，只有第一个单元格似乎显示了imageview。

我该如何解决这个问题？任何帮助表示赞赏。谢谢。