Modify excel cell

Question

Good morning, I would like to edit some cells from already existing excell file. I tried use EPPlus and normal OpenXml classes. However I failed. In both situation program won't crash but always return old (not modified) excel. Please, what am I doing wrong?

Trial 1 - EPPlus:

MemoryStream memoryStream = new MemoryStream();
using (var fs = new FileStream(@"Path\Test.xlsx", FileMode.Open, FileAccess.Read))
{
    byte[] buffer = new byte[1024];
    int bytesRead = 0;
    while ((bytesRead = fs.Read(buffer, 0, buffer.Length)) > 0)
    {
        memoryStream.Write(buffer, 0, bytesRead);
    }
}

using (ExcelPackage excelPackage = new ExcelPackage(memoryStream))
{
    ExcelWorkbook excelWorkBook = excelPackage.Workbook;
    ExcelWorksheet excelWorksheet = excelWorkBook.Worksheets.First();
    excelWorksheet.Cells[1, 1].Value = "Test";
    excelWorksheet.Cells[3, 2].Value = "Test2";
    excelWorksheet.Cells[3, 3].Value = "Test3";

    excelPackage.Save();
}

memoryStream.Position = 0;
return new FileStreamResult(memoryStream, "application/xlsx")
{
    FileDownloadName = "Tester.xlsx"
};

How i said it returns old excel. But in debug mode it contains new value also. It looks like memoryStream cannot be modified.

Trial 2 - OpenXml classes

Stream stream = System.IO.File.Open(@"Path\Test.xlsx", FileMode.Open);
using (SpreadsheetDocument spreadSheet = SpreadsheetDocument.Open(stream, true))
{
    WorksheetPart worksheetPart = GetWorksheetPartByName(spreadSheet, "Sheet1");

    Cell cell = GetCell(worksheetPart.Worksheet, "C", 3);
    cell.CellValue = new CellValue("Testos");
    cell.DataType = new EnumValue<CellValues>(CellValues.String);
    worksheetPart.Worksheet.Save();
}

stream.Position = 0;

return new FileStreamResult(stream, "application/xlsx")
{
    FileDownloadName = "Tester.xlsx"
};

And helper methods:

private static Row GetRow(Worksheet worksheet, uint rowIndex)
{
    Row row;
    if (worksheet.GetFirstChild<SheetData>().Elements<Row>().Where(r => r.RowIndex == rowIndex).Count() != 0)
    {
        row = worksheet.Elements<Row>().Where(r => r.RowIndex == rowIndex).FirstOrDefault();
    }
    else
    {
        row = new Row() { RowIndex = rowIndex };
        worksheet.Append(row);
    }
    return row;
}

private static Cell GetCell(Worksheet worksheet, string columnName, uint rowIndex)
{
    Row row = GetRow(worksheet, rowIndex);

    string cellReference = columnName + rowIndex;
    if (row.Elements<Cell>().Where(c => c.CellReference.Value == columnName + rowIndex).Count() > 0)
    {
        return row.Elements<Cell>().Where(c => c.CellReference.Value == cellReference).FirstOrDefault();
    }
    else
    {
        Cell refCell = null;
        foreach (Cell cell in row.Elements<Cell>())
        {
            if (string.Compare(cell.CellReference.Value, cellReference, true) > 0)
            {
                refCell = cell;
                break;
            }
        }

        Cell newCell = new Cell() { CellReference = cellReference };
        row.InsertBefore(newCell, refCell);

        worksheet.Save();
        return newCell;
    }
}

private static WorksheetPart GetWorksheetPartByName(SpreadsheetDocument document, string sheetName)
{
    IEnumerable<Sheet> sheets = document.WorkbookPart.Workbook.GetFirstChild<Sheets>().Elements<Sheet>().Where(s => s.Name == sheetName);

    string relationshipId = sheets.First().Id.Value;
    WorksheetPart worksheetPart = (WorksheetPart)document.WorkbookPart.GetPartById(relationshipId);
    return worksheetPart;
}

Once more thank you for help.

Answer 1

The problem in both cases is that the modified workbook is not saved back to the stream:

MemoryStream ms = new MemoryStream();
using (FileStream fs = File.OpenRead(@"Path\Test.xlsx"))
using (ExcelPackage excelPackage = new ExcelPackage(fs))
{
    ExcelWorkbook excelWorkBook = excelPackage.Workbook;
    ExcelWorksheet excelWorksheet = excelWorkBook.Worksheets.First();
    excelWorksheet.Cells[1, 1].Value = "Test";
    excelWorksheet.Cells[3, 2].Value = "Test2";
    excelWorksheet.Cells[3, 3].Value = "Test3";

    excelPackage.SaveAs(ms); // This is the important part.
}

ms.Position = 0;
return new FileStreamResult(ms, "application/xlsx")
{
    FileDownloadName = "Tester.xlsx"
};