internal static SelectionRange GetRange(this CollectionViewGroup collectionViewGroup, DataGridContext dataGridContext)
{
int startIndex = -1;
int endIndex = -1;
DataGridVirtualizingCollectionViewGroupBase dataGridVirtualizingCollectionViewGroupBase = collectionViewGroup as DataGridVirtualizingCollectionViewGroupBase;
DataGridCollectionViewGroup dataGridCollectionViewGroup = collectionViewGroup as DataGridCollectionViewGroup;
if (dataGridVirtualizingCollectionViewGroupBase != null)
{
startIndex = dataGridVirtualizingCollectionViewGroupBase.StartGlobalIndex;
endIndex = startIndex + dataGridVirtualizingCollectionViewGroupBase.VirtualItemCount - 1;
}
else if (dataGridCollectionViewGroup != null)
{
startIndex = dataGridCollectionViewGroup.GetFirstRawItemGlobalSortedIndex();
endIndex = startIndex + dataGridCollectionViewGroup.GlobalRawItemCount - 1;
}
else if (collectionViewGroup.ItemCount > 0)
{
if (dataGridContext == null)
{
throw new DataGridInternalException("This collectionViewGroup require a DataGridContext instance");
}
var firstItem = collectionViewGroup.GetFirstLeafItem();
var lastItem = collectionViewGroup.GetLastLeafItem();
if (firstItem != null && lastItem != null)
{
startIndex = dataGridContext.Items.IndexOf(firstItem);
endIndex = dataGridContext.Items.IndexOf(lastItem);
}
}
return((startIndex >= 0) && (startIndex <= endIndex)
? new SelectionRange(startIndex, endIndex)
: SelectionRange.Empty);
}
