private async void RequestImageForCell(UIEntityTableViewCell <TEntity> cell, NSIndexPath indexPath)
{
UIImage image = this.TryGetImageForCell(cell);
if (image != null)
{
cell.SetImage(image);
}
else
{
string imageUrl = cell.ImageUrl;
RemoteImageRequest imageRequest = this.imageCatalog.StartImageRequest(imageUrl, cell.ImageOptions);
if (!imageRequest.IsRequestCompleted)
{
cell.SetImageDownloadInProgress();
}
ServiceResult result = await imageRequest.Task;
// Check if the requesting cell was new and ensure that it hasn't already been reused.
if (indexPath.Length == 0 && imageUrl == cell.ImageUrl)
{
this.SetImageFromResult(result, cell);
}
else
{
this.SetImageFromResult(result, indexPath);
}
}
}
private void SetImageFromResult(ServiceResult result, UIEntityTableViewCell <TEntity> cell)
{
if (cell != null)
{
if (result.ResultCode == ServiceResultCode.Success)
{
UIImage image = this.TryGetImageForCell(cell);
if (image == null)
{
// is it possible the image was automatically removed from the cache in such a short period of time?
throw new InvalidOperationException("An image was not found in the cache.");
}
cell.SetImage(image);
}
else
{
UIImage errorImage =
result.ResultCode == ServiceResultCode.NetworkUnavailable
? this.GetDisconnectedImage()
: this.GetImageDownloadFailedImage(result);
UIViewContentMode contentMode = UIViewContentMode.Center;
UIImageView imageView = cell.GetImageView();
if (errorImage != null &&
(errorImage.Size.Width > imageView.Bounds.Width ||
errorImage.Size.Height > imageView.Bounds.Height))
{
contentMode = UIViewContentMode.ScaleAspectFit;
}
cell.SetImage(errorImage, contentMode);
}
cell.MarkImageDownloadComplete(result.ResultCode == ServiceResultCode.Success);
}
}
