hi! I create an empty template in excel. I would like to open the template and edit the document but I do not know how to change the existing sheet. That's the code: using (SpreadsheetDocument xl = SpreadsheetDocument.Open(filename, true)) { WorkbookPart wbp = xl.WorkbookPart; WorkbookPart workbook = xl.WorkbookPart; // Get the worksheet with the required name. // To be used to match the ID for the required sheet data // because the Sheet class and the SheetData class aren't // linked to each other directly. Sheet s = null; if (wbp.Workbook.Sheets.Elements().Count(nm = nm.Name == sheetName) == 0) { // no such sheet with that name xl.Close(); return; } else { s = (Sheet)wbp.Workbook.Sheets.Elements().Where(nm = nm.Name == sheetName).First(); } WorksheetPart wsp = (WorksheetPart)xl.WorkbookPart.GetPartById(s.Id.Value); Worksheet worksheet = new Worksheet(); SheetData sd = new SheetData(); //SheetData sd = (SheetData)wsp.Worksheet.GetFirstChild(); Stylesheet styleSheet = workbook.WorkbookStylesPart.Stylesheet; //SheetData sheetData = new SheetData(); //build the formatted header style UInt32Value headerFontIndex = util.CreateFont( styleSheet, "Arial", 10, true, System.Drawing.Color.Red); //build the formatted date style UInt32Value dateFontIndex = util.CreateFont( styleSheet, "Arial", 8, true, System.Drawing.Color.Black); //set the background color style UInt32Value headerFillIndex = util.CreateFill( styleSheet, System.Drawing.Color.Black); //create the cell style by combining font/background UInt32Value headerStyleIndex = util.CreateCellFormat( styleSheet, headerFontIndex, headerFillIndex, null); /* * Create a set of basic cell styles for specific formats... * If you are controlling your table then you can simply create the styles you need, * this set of code is still intended to be generic. */ _numberStyleId = util.CreateCellFormat(styleSheet, null, null, UInt32Value.FromUInt32(3)); _doubleStyleId = util.CreateCellFormat(styleSheet, null, null, UInt32Value.FromUInt32(4)); _dateStyleId = util.CreateCellFormat(styleSheet, null, null, UInt32Value.FromUInt32(14)); _textStyleId = util.CreateCellFormat(styleSheet, headerFontIndex, headerFillIndex, null); _percentageStyleId = util.CreateCellFormat(styleSheet, null, null, UInt32Value.FromUInt32(9)); util.AddNumber(xl, sheetName, (UInt32)3, "E", "27", _numberStyleId); util.AddNumber(xl, sheetName, (UInt32)3, "F", "3.6", _doubleStyleId); util.AddNumber(xl, sheetName, (UInt32)5, "L", "5", _percentageStyleId); util.AddText(xl, sheetName, (UInt32)5, "M", "Dario", _textStyleId); util.AddDate(xl, sheetName, (UInt32)3, "J", DateTime.Now, _dateStyleId); util.AddImage(xl, sheetName, imagePath, "Smile", "Smile", 30, 30); util.MergeCells(xl, sheetName, "D12", "F12"); //util.DeleteValueCell(spreadsheet, sheetName, "F", (UInt32)8); txtCellText.Text = util.GetCellValue(xl, sheetName, (UInt32)5, "M"); double number = util.GetCellDoubleValue(xl, sheetName, (UInt32)3, "E"); double numberD = util.GetCellDoubleValue(xl, sheetName, (UInt32)3, "F"); DateTime datee = util.GetCellDateTimeValue(xl, sheetName, (UInt32)3, "J"); //txtDoubleCell.Text = util.GetCellValue(spreadsheet, sheetName, (UInt32)3, "P"); txtPercentualeCell.Text = util.GetCellValue(xl, sheetName, (UInt32)5, "L"); string date = util.GetCellValue(xl, sheetName, (UInt32)3, "J"); double dateD = Convert.ToDouble(date); DateTime dateTime = DateTime.FromOADate(dateD); txtDateCell.Text = dateTime.ToShortDateString(); //worksheet.Append(sd); /* Columns columns = new Columns(); columns.Append(util.CreateColumnData(10, 10, 40)); worksheet.Append(columns); */ SheetProtection sheetProtection1 = new SheetProtection() { Sheet = true, Objects = true, Scenarios = true, SelectLockedCells = true, SelectUnlockedCells = true }; worksheet.Append(sheetProtection1); wsp.Worksheet = worksheet; wsp.Worksheet.Save(); xl.WorkbookPart.Workbook.Save(); xl.Close(); thanks!