/// <summary>
/// Returns the size of the container for a given item. The size can come from the container, a lookup, or a guess depending
/// on the virtualization state of the item.
/// </summary>
/// <param name="itemsControl">
/// <param name="item">
/// <param name="index">
/// <param name="container">returns the container for the item; null if the container wasn't found
/// <returns></returns>
private double GetContainerHeightForItem(ItemsControl itemsControl, int index)
{
double height;
if (cachedSizes.ContainsSize(index))
{
height = cachedSizes[index];
}
else
{
height = cachedSizes.GetMax();
}
return(height);
}
