What indicates an Office Open XML Cell contains a Date/Time value?

Question

I\'m reading an .xlsx file using the Office Open XML SDK and am confused about reading Date/Time values. One of my spreadsheets has this markup (generated by Excel 2010)

Answer 1

Thought I'd add my solution that I've put together to determine if the double value FromOADate is really a date or not. Reason being is I have a zip code in my excel file as well. The numberingFormat will be null if it's text.

Alternatively you could use the numberingFormatId and check against a list of Ids that Excel uses for dates.

In my case I've explicitly determined the formatting of all fields for the client.

    /// 

    /// Creates the datatable and parses the file into a datatable
    /// 
    /// the file upload's filename
    private void ReadAsDataTable(string fileName)
    {
        try
        {
            DataTable dt = new DataTable();
            using (SpreadsheetDocument spreadSheetDocument = SpreadsheetDocument.Open(string.Format("{0}/{1}", UploadPath, fileName), false))
            {
                WorkbookPart workbookPart = spreadSheetDocument.WorkbookPart;
                IEnumerable sheets = spreadSheetDocument.WorkbookPart.Workbook.GetFirstChild().Elements();
                string relationshipId = sheets.First().Id.Value;
                WorksheetPart worksheetPart = (WorksheetPart)spreadSheetDocument.WorkbookPart.GetPartById(relationshipId);
                Worksheet workSheet = worksheetPart.Worksheet;
                SheetData sheetData = workSheet.GetFirstChild();
                IEnumerable rows = sheetData.Descendants();

                var cellFormats = workbookPart.WorkbookStylesPart.Stylesheet.CellFormats;
                var numberingFormats = workbookPart.WorkbookStylesPart.Stylesheet.NumberingFormats;

                // columns omitted for brevity

                // skip first row as this row is column header names
                foreach (Row row in rows.Skip(1))
                {
                    DataRow dataRow = dt.NewRow();

                    for (int i = 0; i < row.Descendants().Count(); i++)
                    {
                        bool isDate = false;
                        var styleIndex = (int)row.Descendants().ElementAt(i).StyleIndex.Value;
                        var cellFormat = (CellFormat)cellFormats.ElementAt(styleIndex);

                        if (cellFormat.NumberFormatId != null)
                        {
                            var numberFormatId = cellFormat.NumberFormatId.Value;
                            var numberingFormat = numberingFormats.Cast()
                                .SingleOrDefault(f => f.NumberFormatId.Value == numberFormatId);

                            // Here's yer string! Example: $#,##0.00_);[Red]($#,##0.00)
                            if (numberingFormat != null && numberingFormat.FormatCode.Value.Contains("mm/dd/yy"))
                            {
                                string formatString = numberingFormat.FormatCode.Value;
                                isDate = true;
                            }
                        }

                        // replace '-' with empty string
                        string value = GetCellValue(spreadSheetDocument, row.Descendants().ElementAt(i), isDate);
                        dataRow[i] = value.Equals("-") ? string.Empty : value;
                    }

                    dt.Rows.Add(dataRow);
                }
            }

            this.InsertMembers(dt);
            dt.Clear();
        }
        catch (Exception ex)
        {
            LogHelper.Error(typeof(MemberUploadApiController), ex.Message, ex);
        }
    }

    /// 

    /// Reads the cell's value
    /// 
    /// current document
    /// the cell to read
    /// cell's value
    private string GetCellValue(SpreadsheetDocument document, Cell cell, bool isDate)
    {
        string value = string.Empty;

        try
        {
            SharedStringTablePart stringTablePart = document.WorkbookPart.SharedStringTablePart;
            value = cell.CellValue.InnerXml;

            if (cell.DataType != null && cell.DataType.Value == CellValues.SharedString)
            {
                return stringTablePart.SharedStringTable.ChildElements[Int32.Parse(value)].InnerText;
            }
            else
            {
                // check if this is a date or zip.
                // integers will be passed into this else statement as well. 
                if (isDate)
                {
                    value = DateTime.FromOADate(double.Parse(value)).ToString();
                }

                return value;
            }
        }
        catch (Exception ex)
        {
            LogHelper.Error(typeof(MemberUploadApiController), ex.Message, ex);
        }

        return value;
    }