I have written this class to write a collection of any type to an excel file:

public static class ExcelWriter
{
    public static void WriteToExcelFile(IEnumerable<object> collection, string filePath)
    {
        if (collection?.Any() != true || String.IsNullOrWhiteSpace(filePath))
            return;

        if (File.Exists(filePath))
            File.Delete(filePath);

        using (var document = SpreadsheetDocument.Create(filePath, SpreadsheetDocumentType.Workbook))
        {
            WorkbookPart workbookPart = document.AddWorkbookPart();
            workbookPart.Workbook = new Workbook();

            WorksheetPart worksheetPart = workbookPart.AddNewPart<WorksheetPart>();
            worksheetPart.Worksheet = new Worksheet();

            Sheets sheets = workbookPart.Workbook.AppendChild(new Sheets());

            Sheet sheet = new Sheet()
            {
                Id = workbookPart.GetIdOfPart(worksheetPart),
                SheetId = 1,
                Name = "Sheet1"
            };

            sheets.Append(sheet);

            workbookPart.Workbook.Save();

            SheetData sheetData = worksheetPart.Worksheet.AppendChild(new SheetData());

            sheetData.AppendChild(generateHeaderRow(collection.First().GetType()));

            foreach (var item in collection)
            {
                sheetData.AppendChild(generateValuesRow(item));
            }

            worksheetPart.Worksheet.Save();
        }
    }

    private static Row generateHeaderRow(Type dataType)
    {
        var propertyNames = dataType.GetProperties().Select(p => p.Name).ToList();

        var headerCells = new Cell[propertyNames.Count];
        for (int i = 0; i < propertyNames.Count; i++)
        {
            headerCells[i] = createCell(propertyNames[i], CellValues.String);
        }

        return new Row(headerCells);
    }

    private static Row generateValuesRow(object rowData)
    {
        var cells = new List<Cell>();

        foreach (var property in rowData.GetType().GetProperties())
        {
            var propertyValue = property.GetValue(rowData);
            cells.Add(createCell(propertyValue.ToString(), getCellValueByType(propertyValue)));
        }

        return new Row(cells);
    }

    private static CellValues getCellValueByType(object propertyValue)
    {
        string propertyValueString = propertyValue.ToString();
        if (Double.TryParse(propertyValueString, out _))
        {
            return CellValues.Number;
        }
        if (DateTime.TryParse(propertyValueString, out _))
        {
            return CellValues.Date;
        }
        if (Boolean.TryParse(propertyValueString, out _))
        {
            return CellValues.Boolean;
        }

        return CellValues.String;
    }

    private static Cell createCell(string value, CellValues dataType)
    {
        return new Cell()
        {
            CellValue = new CellValue(value),
            DataType = new EnumValue<CellValues>(dataType)
        };
    }
}

This actually generates the excel file, but when I open that file in Excel web it opens in Viewing mode and says you need to repair it, in order to edit(Excel can't repair it though):

I changed my code to work with a specific type and it worked without this issue. That code looks like this:

public class TypeDependentWriter
{
    public static void WriteToExcelFile(IEnumerable<TestDataType> collection, string filePath)
    {
        if (collection?.Any() != true || String.IsNullOrWhiteSpace(filePath))
            return;

        if (File.Exists(filePath))
            File.Delete(filePath);

        using (var document = SpreadsheetDocument.Create(filePath, SpreadsheetDocumentType.Workbook))
        {
            WorkbookPart workbookPart = document.AddWorkbookPart();
            workbookPart.Workbook = new Workbook();

            WorksheetPart worksheetPart = workbookPart.AddNewPart<WorksheetPart>();
            worksheetPart.Worksheet = new Worksheet();

            Sheets sheets = workbookPart.Workbook.AppendChild(new Sheets());

            Sheet sheet = new Sheet()
            {
                Id = workbookPart.GetIdOfPart(worksheetPart),
                SheetId = 1,
                Name = "Sheet1"
            };

            sheets.Append(sheet);

            workbookPart.Workbook.Save();

            SheetData sheetData = worksheetPart.Worksheet.AppendChild(new SheetData());

            // Header row.
            Row row = new Row();

            row.Append(
                createCell("Id", CellValues.String),
                createCell("Name", CellValues.String),
                createCell("Birth Date", CellValues.String));

            sheetData.AppendChild(row);

            // Data rows.
            foreach (var item in collection)
            {
                row = new Row();

                row.Append(
                    createCell(item.Id.ToString(), CellValues.Number),
                    createCell(item.Name, CellValues.String),
                    createCell(item.DateOfBirth.ToString("yyyy/MM/dd"), CellValues.String));

                sheetData.AppendChild(row);
            }

            worksheetPart.Worksheet.Save();
        }
    }

    private static Cell createCell(string value, CellValues dataType)
    {
        return new Cell()
        {
            CellValue = new CellValue(value),
            DataType = new EnumValue<CellValues>(dataType)
        };
    }
}

How can I make the first code work?