public BinaryTreeNode(Hotel _data)
{
this.data = _data;
left = null;
right = null;
}
private void btnStaffSortDescRate_Click(object sender, EventArgs e)
{
selectedHotel = Singleton.Instance().hotels.nodes[dgwHotels.CurrentCell.RowIndex];
dgwStaff.DataSource = selectedHotel.Staff.OrderByDescending(x => x.Rate).ToList();
}