OpenXML - change Excel cell format (Date and Number) when exporting from Datagridview

Question

I using OpenXML to export Datagridview to Excel. If I export cells with CellValues.String evertyhing works fine without any errors in Excel file, but what I need is to prope

Answer 1

There seems to be a lot of answers to this type of question that result in an excel that asks to be repaired. I'd normally recommend people use ClosedXML, but if OpenXML is a must then the answer given here: https://stackoverflow.com/a/31829959/994679 does work.

Here's that answer with some extra lines for Date including time cells, number cells, and string cells.

    private static void TestExcel()
    {
        using (var Spreadsheet = SpreadsheetDocument.Create("C:\\Example.xlsx", SpreadsheetDocumentType.Workbook))
        {
            // Create workbook.
            var WorkbookPart = Spreadsheet.AddWorkbookPart();
            var Workbook = WorkbookPart.Workbook = new Workbook();

            // Add Stylesheet.
            var WorkbookStylesPart = WorkbookPart.AddNewPart();
            WorkbookStylesPart.Stylesheet = GetStylesheet();
            WorkbookStylesPart.Stylesheet.Save();

            // Create worksheet.
            var WorksheetPart = Spreadsheet.WorkbookPart.AddNewPart();
            var Worksheet = WorksheetPart.Worksheet = new Worksheet();

            // Add data to worksheet.
            var SheetData = Worksheet.AppendChild(new SheetData());
            SheetData.AppendChild(new Row(
                //Date example. Will show as dd/MM/yyyy. 
                new Cell() { CellValue = new CellValue(DateTime.Today.ToOADate().ToString(CultureInfo.InvariantCulture)), StyleIndex = 1 },

                //Date Time example. Will show as dd/MM/yyyy HH:mm
                new Cell() { CellValue = new CellValue(DateTime.Now.ToOADate().ToString(CultureInfo.InvariantCulture)), StyleIndex = 2 },

                //Number example
                new Cell() { CellValue = new CellValue(123.23d.ToString(CultureInfo.InvariantCulture)), StyleIndex = 0 },

                //String example
                new Cell() { CellValue = new CellValue("Test string"), DataType = CellValues.String }

            ));

            // Link worksheet to workbook.
            var Sheets = Workbook.AppendChild(new Sheets());
            Sheets.AppendChild(new Sheet()
            {
                Id = WorkbookPart.GetIdOfPart(WorksheetPart),
                SheetId = (uint)(Sheets.Count() + 1),
                Name = "Example"
            });

            Workbook.Save();
        }
    }

    private static Stylesheet GetStylesheet()
    {
        var StyleSheet = new Stylesheet();

        // Create "fonts" node.
        var Fonts = new Fonts();
        Fonts.Append(new Font()
        {
            FontName = new FontName() { Val = "Calibri" },
            FontSize = new FontSize() { Val = 11 },
            FontFamilyNumbering = new FontFamilyNumbering() { Val = 2 },
        });

        Fonts.Count = (uint)Fonts.ChildElements.Count;

        // Create "fills" node.
        var Fills = new Fills();
        Fills.Append(new Fill()
        {
            PatternFill = new PatternFill() { PatternType = PatternValues.None }
        });
        Fills.Append(new Fill()
        {
            PatternFill = new PatternFill() { PatternType = PatternValues.Gray125 }
        });

        Fills.Count = (uint)Fills.ChildElements.Count;

        // Create "borders" node.
        var Borders = new Borders();
        Borders.Append(new Border()
        {
            LeftBorder = new LeftBorder(),
            RightBorder = new RightBorder(),
            TopBorder = new TopBorder(),
            BottomBorder = new BottomBorder(),
            DiagonalBorder = new DiagonalBorder()
        });

        Borders.Count = (uint)Borders.ChildElements.Count;

        // Create "cellStyleXfs" node.
        var CellStyleFormats = new CellStyleFormats();
        CellStyleFormats.Append(new CellFormat()
        {
            NumberFormatId = 0,
            FontId = 0,
            FillId = 0,
            BorderId = 0
        });

        CellStyleFormats.Count = (uint)CellStyleFormats.ChildElements.Count;

        // Create "cellXfs" node.
        var CellFormats = new CellFormats();

        // StyleIndex = 0, A default style that works for most things (But not strings? )
        CellFormats.Append(new CellFormat()
        {
            BorderId = 0,
            FillId = 0,
            FontId = 0,
            NumberFormatId = 0,
            FormatId = 0,
            ApplyNumberFormat = true
        });

        // StyleIndex = 1, A style that works for DateTime (just the date)
        CellFormats.Append(new CellFormat()
        {
            BorderId = 0,
            FillId = 0,
            FontId = 0,
            NumberFormatId = 14, //Date
            FormatId = 0,
            ApplyNumberFormat = true
        });

        // StyleIndex = 2, A style that works for DateTime (Date and Time)
        CellFormats.Append(new CellFormat()
        {
            BorderId = 0,
            FillId = 0,
            FontId = 0,
            NumberFormatId = 22, //Date Time
            FormatId = 0,
            ApplyNumberFormat = true
        });

        CellFormats.Count = (uint)CellFormats.ChildElements.Count;

        // Create "cellStyles" node.
        var CellStyles = new CellStyles();
        CellStyles.Append(new CellStyle()
        {
            Name = "Normal",
            FormatId = 0,
            BuiltinId = 0
        });
        CellStyles.Count = (uint)CellStyles.ChildElements.Count;

        // Append all nodes in order.
        StyleSheet.Append(Fonts);
        StyleSheet.Append(Fills);
        StyleSheet.Append(Borders);
        StyleSheet.Append(CellStyleFormats);
        StyleSheet.Append(CellFormats);
        StyleSheet.Append(CellStyles);

        return StyleSheet;
    }