private void CleanUpMemory(int cleanRange)
{
int currentIndex = PreviewItems.IndexOf(SelectedPreview);
int previewItemsCount = PreviewItems.Count - 1;
switch (GalleryDirection)
{
case GalleryDirection.Next:
if ((currentIndex - cleanRange) >= 0)
{
int cleanIndex = currentIndex - cleanRange;
if (PreviewItems[cleanIndex].IsBusy)
{
PreviewItems[cleanIndex].CancelPreviewRequest();
}
PreviewItems[cleanIndex].InViewingRange = false;
PreviewItems[cleanIndex].PreviewImageUri = null;
}
break;
case GalleryDirection.Previous:
if ((currentIndex + cleanRange) <= previewItemsCount)
{
int cleanIndex = currentIndex + cleanRange;
if (PreviewItems[cleanIndex].IsBusy)
{
PreviewItems[cleanIndex].CancelPreviewRequest();
}
PreviewItems[cleanIndex].InViewingRange = false;
PreviewItems[cleanIndex].PreviewImageUri = null;
}
break;
}
}
/// <summary>
/// Set the range of previews to load before and after the current preview.
/// </summary>
/// <param name="viewRange">Range from the current item to load the previews.</param>
/// <param name="initialize">Indicates if is an initialization.</param>
/// <exception cref="ArgumentOutOfRangeException"/>
private void SetViewingRange(int viewRange, bool initialize)
{
if (SelectedPreview == null)
{
return;
}
int currentIndex = PreviewItems.IndexOf(SelectedPreview);
int lowIndex = currentIndex - viewRange;
if (lowIndex < 0)
{
lowIndex = 0;
}
int highIndex = currentIndex + viewRange;
if (highIndex > PreviewItems.Count - 1)
{
highIndex = PreviewItems.Count - 1;
}
if (initialize)
{
for (int i = currentIndex; i >= lowIndex; i--)
{
PreviewItems[i].InViewingRange = true;
}
for (int i = currentIndex; i <= highIndex; i++)
{
PreviewItems[i].InViewingRange = true;
}
}
else
{
switch (GalleryDirection)
{
case GalleryDirection.Next:
default:
PreviewItems[highIndex].InViewingRange = true;
break;
case GalleryDirection.Previous:
PreviewItems[lowIndex].InViewingRange = true;
break;
}
}
}