protected override void Layout()
{
var count = Rect.Height / ItemHeight + 1;
var index = m_scrollY / ItemHeight;
var y = Rect.Y + (index * ItemHeight - m_scrollY);
int i = 0;
for (; i < count; ++i, ++index)
{
ListItemRegion <T> r = null;
if (i < Children.Count)
{
r = Children[i] as ListItemRegion <T>;
}
else
{
r = m_source.CreateItem();
r.Parent = this;
r.MouseLeftClicked += x => R_LeftClicked(x as ListItemRegion <T>);
r.MouseLeftDoubleClicked += x => R_LeftDoubleClicked(x as ListItemRegion <T>);
Children.Add(r);
}
r.Rect = new Rect(Rect.X, y, Rect.Width, ItemHeight);
if (index < 0 || index >= m_source.Count)
{
r.SourceIndex = null;
}
else
{
r.SourceIndex = index;
}
y += ItemHeight;
}
Invalidate();
}