I used the code provided by Andrew J, but the DataType
CellValues.Date
produced a corrupted xlsx-file for me.
The DataType
CellValues.Number
worked fine for me (Don't forget to set NumberFormatId
):
cell.DataType = new EnumValue<CellValues>(CellValues.Number);
My whole code:
DateTime valueDate = DateTime.Now;
string valueString = valueDate.ToOADate().ToString();
CellValue cellValue = new CellValue(valueString);
Cell cell = new Cell();
cell.DataType = new EnumValue<CellValues>(CellValues.Number);
cell.StyleIndex = yourStyle; //StyleIndex of CellFormat cfBaseDate -> See below
cell.Append(cellValue);
My CellFormat for this cell in the Stylesheet looks like:
CellFormat cfBaseDate = new CellFormat() {
ApplyNumberFormat = true,
NumberFormatId = 14, //14 is a localized short Date (d/m/yyyy) -> See list below
//Some further styling parameters
};
If you'd like to format your date another way, here is a list of all default Excel NumberFormatId
's
ID FORMAT CODE
0 General
1 0
2 0.00
3 #,##0
4 #,##0.00
9 0%
10 0.00%
11 0.00E+00
12 # ?/?
13 # ??/??
14 d/m/yyyy
15 d-mmm-yy
16 d-mmm
17 mmm-yy
18 h:mm tt
19 h:mm:ss tt
20 H:mm
21 H:mm:ss
22 m/d/yyyy H:mm
37 #,##0 ;(#,##0)
38 #,##0 ;[Red](#,##0)
39 #,##0.00;(#,##0.00)
40 #,##0.00;[Red](#,##0.00)
45 mm:ss
46 [h]:mm:ss
47 mmss.0
48 ##0.0E+0
49 @
Source of list: https://github.com/ClosedXML/ClosedXML/wiki/NumberFormatId-Lookup-Table
I know this list is from ClosedXML, but it's the same in OpenXML.