Use the RowSel and ColSel properties to modify a selection or to determine which cells are currently selected. Columns and rows are numbered from zero, beginning at the top for rows and at the left for columns.
Setting the Row and Col properties automatically collapses the selection to a single cell, resetting the RowSel and ColSel properties. Therefore, to specify a block selection, you must Row and Col, then RowSel and ColSel. Alternatively, you may use the Select(CellRange,Boolean) method to select a range with a single statement.
When a range is selected, the value of Row may be greater than or less than RowSel, and Col may be greater than or less than ColSel. This is inconvenient when you need to set up bounds for loops. In these cases, you can use the Selection property to retrieve a normalized CellRange object, where r1 <= r2 and c1 <= c2.
CellRange rg = flex.Selection; for (int r = rg.r1; r <= rg.r2; r++) for (int c = rg.c1; c <= rg.c2; c++) Console.WriteLine("the value at {0} {1} is {2}", r, c, flex[r, c]);