public int Add(object dataItem)
{
if (OwningGrid.SelectionMode == DataGridSelectionMode.Single)
{
throw DataGridError.DataGridSelectedItemsCollection.CannotChangeSelectedItemsCollectionInSingleMode();
}
int itemIndex = OwningGrid.DataConnection.IndexOf(dataItem);
if (itemIndex == -1)
{
throw DataGridError.DataGrid.ItemIsNotContainedInTheItemsSource("dataItem");
}
Debug.Assert(itemIndex >= 0);
int slot = OwningGrid.SlotFromRowIndex(itemIndex);
if (_selectedSlotsTable.RangeCount == 0)
{
OwningGrid.SelectedItem = dataItem;
}
else
{
OwningGrid.SetRowSelection(slot, true /*isSelected*/, false /*setAnchorSlot*/);
}
return(_selectedSlotsTable.IndexOf(slot));
}
