The Weird and The Wonderful

/// <summary>
/// Gets and sets the selected indexes
/// </summary>
/// <remarks>
/// This is necessarily complicated.
/// Remember, the data comes from a DataTable (DT) - (or a list from which the DT data
/// was derived) and the outside world expects indexes to to relative to that DT.
/// But...we display the data in a DataGridView (DGV) via a DataView (DV) and apply
/// filtering and sorting to the DV according to the user input.
/// So the selected rows we get from the DGV are in last-selected-by-user order, (which
/// if fine and dandy), but are relative to the DGV rather than the underlying DV or
/// DT data source, as the DGV is subject to the sorting and filtering applied to the DV.
///
/// So, we get the selected items from the DGV (only place we can, the DV doesn't know
/// about selection), then have to convert that to the DataRow and get the index of that
/// from the DT. But (of course) the DGV returns a DataGridViewRow object just to be
/// annoying...
/// And that's just Get!
/// </remarks>
[Browsable(false),
DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public IEnumerable<int> SelectedIndexes
    {
    get { return dgvData.SelectedRows.Cast<DataGridViewRow>().Select(r => _DataSource.Rows.IndexOf(((DataRowView)r.DataBoundItem).Row)); }
    set { ... }
    }