public void ShowElement(int x)
{
if (ItemsSource == null)
{
return;
}
var objs = new object[ItemsSource.Count];
ItemsSource.CopyTo(objs, 0);
var minX = x - CacheWidth;
var maxX = x + CacheWidth;
var countMinX = 0;
var countMaxX = ItemsSource.Count - 1;
if (ElementWidth > 0)
{
countMinX = minX / ElementWidth;
countMaxX = maxX / ElementWidth - 1;
countMinX = Math.Max(0, countMinX);
countMaxX = Math.Min(ItemsSource.Count - 1, countMaxX);
}
// TODO optimize it
for (int i = countMinX; i <= countMaxX; i++)
{
if (elements[i] != null)
{
continue;
}
// Add view
var o = CreateContent() as View;
if (o != null)
{
o.BindingContext = objs[i];
Children.Add(o, new Point((double)i * ElementWidth, 0.0));
elements[i] = o;
if (Added != null)
{
Added(i, objs[i]);
}
}
}
for (int i = 0; i < elements.Count; i++)
{
if (countMinX <= i && i <= countMaxX)
{
continue;
}
if (elements[i] == null)
{
continue;
}
// Remove view
Children.Remove(elements[i]);
elements[i] = null;
if (Removed != null)
{
Removed(i, objs[i]);
}
}
}