New Post: Excel Data Type

Data type seems doesn't work for Excel. For example, I set value of cell (1,1) as number 1 and its datatype as number below.
ws.Cell(1,1).Value = 1;
ws.Cell(1,1).DataType = XLCellValues.Number;

After excel file is saved and I open it in Excel, the cell is still 'generic' not 'number'.

Did I miss something?

Thank you.