internal void BringIntoViewCore(BringIntoViewOperation bringIntoViewOperation)
{
if (bringIntoViewOperation == null)
{
return;
}
if (bringIntoViewOperation.ScrollAttempts < BringIntoViewOperation.MaxScrollAttempts)
{
if (this.IsItemInViewport(bringIntoViewOperation.RequestedItem, false))
{
if (bringIntoViewOperation.CompletedAction != null)
{
bringIntoViewOperation.CompletedAction.Invoke();
}
this.UnsubscribeRendering();
}
else
{
this.BringIntoView(bringIntoViewOperation);
bringIntoViewOperation.ScrollAttempts++;
this.scrollUpdateService.RegisterUpdate(new DelegateUpdate(() => this.BringIntoViewCore(bringIntoViewOperation)));
}
}
else
{
this.UnsubscribeRendering();
}
}
/// <summary>
/// Brings the given data item into the viewport and calls the <paramref name="scrollCompletedAction"/> method when the operation is completed.
/// </summary>
/// <param name="item">The item to show.</param>
/// <param name="scrollCompletedAction">Action to be executed when the operation is completed.</param>
public virtual void BringIntoView(object item, Action scrollCompletedAction)
{
if (!this.IsProperlyTemplated)
{
this.initialVirtualizationItem = this.listSource.FindItem(item);
return;
}
var bringIntoViewOperation = new BringIntoViewOperation(item)
{
CompletedAction = scrollCompletedAction, LastAverageItemLength = this.virtualizationStrategy.averageItemLength
};
this.BringIntoViewCore(bringIntoViewOperation);
}
internal virtual void BringIntoView(BringIntoViewOperation bringIntoViewOperation)
{
// Check whether the item to bring into view is already realized
RadVirtualizingDataControlItem foundItem = null;
foreach (RadVirtualizingDataControlItem uiItem in this.realizedItems)
{
if (object.Equals(uiItem.associatedDataItem.Value, bringIntoViewOperation.RequestedItem))
{
foundItem = uiItem;
break;
}
}
// If the item is not realized, recycle all items and start realizing from the pivot item (the one we should bring into view).
if (foundItem == null)
{
this.initialVirtualizationItem = this.listSource.FindItem(bringIntoViewOperation.RequestedItem);
if (this.initialVirtualizationItem == null)
{
throw new ArgumentException("Specified item does not exist in the Items Source.");
}
this.RecycleAllItems();
this.ApplyScrollOffsetForItem(this.initialVirtualizationItem, bringIntoViewOperation.LastAverageItemLength);
this.BeginAsyncBalance();
}
else
{
// If the item is realized, calculate the smallest amount that the item can be offset so that it is fully visible in the viewport.
double offset = this.GetRealizedItemBringIntoViewOffset(foundItem);
this.virtualizationStrategy.ScrollToOffset(
offset,
() =>
{
// Perform a balance to ensure that all buffers are filled.
this.SubscribeRendering();
this.BalanceVisualSpace();
});
}
}
