public Size Measure(Size availableSize)
{
int startIdx, endIdx;
// Figure out range that's visible based on layout algorithm
getVisibleRange(availableSize, out startIdx, out endIdx);
//Add and subtract CacheItemCount to StartIdx and EndIdx.
_panel.UpdateCacheItemCount(ref startIdx, ref endIdx);
//Generate new items and cleaup unused items.
_panel.Generator.Generate(startIdx, endIdx);
_panel.Generator.CleanUp(startIdx, endIdx);
//Output extent so it can be accessed by PanelScrollHelper.
Extent = calculateExtent(availableSize, _panel.getItemCount());
//And return availableSize (take all available).
return(availableSize);
}
/// <summary>
/// Add and subtract CacheItemCount to StartIdx and EndIdx.
/// </summary>
/// <param name="panel"></param>
/// <param name="startIdx"></param>
/// <param name="endIdx"></param>
public static void UpdateCacheItemCount(this IOCPanel panel,
ref int startIdx, ref int endIdx)
{
//Add and subtract CacheItemCount to StartIdx and EndIdx.
int itemCount = panel.getItemCount();
startIdx -= panel.CacheItemCount;
endIdx += panel.CacheItemCount;
if (startIdx < 0)
{
startIdx = 0;
}
if (endIdx > itemCount - 1)
{
endIdx = itemCount - 1;
}
}
