OpenXML - Writing a date into Excel spreadsheet results in unreadable content

Question

I am using the following code to add a DateTime to a column in my spreadsheet:

var dt = DateTime.Now;
r.AppendChild(new Cell()
    {         


        

Answer 1

private Cell CreateCellWithValue(DateTime columnValue, uint? styleIndex, string cellReference)
{
    Cell c = new Cell();
    c.DataType = CellValues.Number;
    c.CellValue = new CellValue(columnValue.ToOADate().ToString(new CultureInfo("en-US")));
    c.CellReference = cellReference;
    c.StyleIndex = styleIndex;

    return c;
}