List string sortColumns new List string dataGridView1 ColumnHeaderMous

List<string> sortColumns  = new List<string>();
            dataGridView1.ColumnHeaderMouseClick += (obj, evnt) =>
            {
                _stack.Push(evnt.ColumnIndex);
                int columns = dataGridView1.Columns.Count;
                int[] array = _stack.Distinct().ToArray();
                var builder = new StringBuilder();
                for (int index = 0; index < array.Length; index++)
                {
                    int i = array[index];
                    if (index >= columns)
                    {
                        break;
                    }

                    DataGridViewColumn gridViewColumn = dataGridView1.Columns[i];
                    string sort = null;
                    switch (gridViewColumn.HeaderCell.SortGlyphDirection)
                    {
                        case System.Windows.Forms.SortOrder.None:
                        case System.Windows.Forms.SortOrder.Ascending:
                            sort = "ASC";
                            break;
                        case System.Windows.Forms.SortOrder.Descending:
                            sort = "DESC";
                            break;
                        default:
                            throw new ArgumentOutOfRangeException();
                    }
                    builder.AppendFormat("{0} {1}, ", gridViewColumn.Name, sort);
                }
                string s = builder.ToString();
                s = s.Remove(s.Length - 2);
                Console.WriteLine(s);
            };