c# - Reading a date from xlsx using open xml sdk

Question

I have a date in format "4/5/2011" (month/day/year) in a xlsx file in one of the cells. Im trying to parse the file and load those data in some classes.

So far the part where I parse the cell looks like this:

string cellValue = cell.InnerText;
if (cell.DataType != null)
{
    switch (cell.DataType.Value)
    {
        case CellValues.SharedString:
            // get string from shared string table
            cellValue = this.GetStringFromSharedStringTable(int.Parse(cellValue));
            break;
    }
}

I hoped that date would be a cell.DataType. The truth is when parsing the cell with the date "4/5/2011", the value of cell.DataType is null and the value of the cell is "40638" and it is not an index to the shared string table. (I have tried that before and it ended up with an exception.)

Any ideas? Thanks

Answer 1

Open XML stores dates as the number of days from 1 Jan 1900. Well, skipping the incorrect 29 Feb 1900 as a valid day. You should be able to find out algorithms to help you calculate the correct value. I believe some developers use DateTime.FromOADate() as a helper.

Also, the Cell class has the DataType property as Number by default. So if it's null, it's a number, which includes dates in our case.

You only go to the shared strings table when the date stored is before the epoch (1 Jan 1900 in this case). And then in that case, the CellValue of the Cell class holds the index to the shared string table.