#!c#

using DocumentFormat.OpenXml.Spreadsheet;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml;

#!c#

File.Copy(SourcetemplateFilePath, DestinationFilePath, true);

#!c#

public void generateExcel(DataTable YoutdTName, string YourExcelfileName)
        {
            // Create cell reference array 
            string[] CellReferenceArray = new string[] { "A", "B", "C", "D", "E" };
            //Open your saved excel file that you have created using template file.
            using (SpreadsheetDocument myDoc = SpreadsheetDocument.Open(YourExcelfileName, true))
            {
                // Create reference of main Workbook part, which contains all reference.
                WorkbookPart objworkbook = myDoc.WorkbookPart;

                // Create style sheet object that will be used for applying styling.
                Stylesheet objstyleSheet = objworkbook.WorkbookStylesPart.Stylesheet;

                // pick up first worksheet
                WorksheetPart objworksheet = objworkbook.WorksheetParts.First();

                // will be used in end while creating sheet data
                string objorigninalSheetId = objworkbook.GetIdOfPart(objworksheet);
                WorksheetPart objreplacementPart = objworkbook.AddNewPart<WorksheetPart>();
                string objreplacementPartId = objworkbook.GetIdOfPart(objreplacementPart);

                // Create object reader to read from excel file.
                OpenXmlReader objreader = OpenXmlReader.Create(objworksheet);

                // create writer object to write in excel sheet.
                OpenXmlWriter objOpenXmwriter = OpenXmlWriter.Create(objreplacementPart);

                int i = 1;
                Row r = new Row();
                Cell c = new Cell();
                Columns col1 = new Columns();
                UInt32 index;

                while (objreader.Read())
                {
                    if (objreader.ElementType == typeof(SheetData))
                    {
                        if (objreader.IsEndElement)
                            continue;

                        objOpenXmwriter.WriteStartElement(new SheetData());
                        objOpenXmwriter.WriteStartElement(r);

                        // Loop to insert header
                        foreach (DataColumn colHead in YoutdTName.Columns)
                        {
                            c = new Cell
                            {
                                DataType = CellValues.String,
                                CellReference = CellReferenceArray[i] + Convert.ToString(index)
                            };
                            CellValue v1 = new CellValue(colHead.ColumnName.ToString());                         
                            c.Append(v1);
                            objOpenXmwriter.WriteElement(c);
                            i += 1;
                        }
                        objOpenXmwriter.WriteEndElement();
                        index += 1;

                        //Loop to insert datatable row in excel    
                        foreach (DataRow dr in YoutdTName.Rows)
                        {
                            objOpenXmwriter.WriteStartElement(r);
                            i = 1;
                            foreach (DataColumn col in YoutdTName.Columns)
                            {
                                c = new Cell
                                {
                                    DataType = CellValues.String,
                                    CellReference = CellReferenceArray[i] + Convert.ToString(index)
                                };
                                CellValue v1 = new CellValue(dr[col].ToString());
                                c.AppendChild(v1);
                                objOpenXmwriter.WriteElement(c);
                                i += 1;
                            }
                            objOpenXmwriter.WriteEndElement();
                            index += 1;
                        }
                        objOpenXmwriter.WriteEndElement();
                    }
                }
                //close all objects
                objreader.Close();
                objOpenXmwriter.Close();

                Sheet sheet = objworkbook.Workbook.Descendants<Sheet>().Where(s => s.Id.Value.Equals(objorigninalSheetId)).First();
                sheet.Id.Value = objreplacementPartId;
                objworkbook.DeletePart(objworksheet);

            }
            //download created excel sheet.
            Response.AddHeader("Content-Disposition", "inline;filename=YourExcelfileName.xlxs");
            Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
            Response.WriteFile("YourExcelfileName.xlxs");
            Response.End();
        }

#!c#

string projectFiles = Path.GetFullPath("../../Files/");

            //Instantiating a Workbook object
            Workbook workbook = new Workbook();

            //Adding a new worksheet to the Workbook object
            int i = workbook.Worksheets.Add();

            //Obtaining the reference of the newly added worksheet by passing its sheet index
            Worksheet worksheet = workbook.Worksheets[i];

            //Creating an array containing names as string values
            string[] names = new string[] { "laurence chen", "roman korchagin", "kyle huang" };

            //Importing the array of names to 1st row and first column vertically
            worksheet.Cells.ImportArray(names, 0, 0, true);

            //Save FIle
            workbook.Save(projectFiles + "Output.xlsx");