[Solved] Writing Data to an Existing Excel File in C#

I want to write data to an existing Excel file, whilst preserving the original data.

The file has sheet1; I want to write on sheet2, then save.
The problem is that every time I save, it will create a new Excel file and overwrite the existing one.

Could anyone provide any help to keep the old data while saving?

I have the following function

using System.Windows.Forms;
using Excel = Microsoft.Office.Interop.Excel; 

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Excel.Application xlApp ;
            Excel.Workbook xlWorkBook ;
            Excel.Worksheet xlWorkSheet ;
            object misValue = System.Reflection.Missing.Value;

            xlApp = new Excel.ApplicationClass();
            xlWorkBook = xlApp.Workbooks.Open("csharp.net-informations.xls", 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "	", false, false, 0, true, 1, 0);
            xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);

            MessageBox.Show(xlWorkSheet.get_Range("A1","A1").Value2.ToString());

            xlWorkBook.Close(true, misValue, misValue);
            xlApp.Quit();

            releaseObject(xlWorkSheet);
            releaseObject(xlWorkBook);
            releaseObject(xlApp);
        }

        private void releaseObject(object obj)
        {
            try
            {
                System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
                obj = null;
            }
            catch (Exception ex)
            {
                obj = null;
                MessageBox.Show("Unable to release the Object " + ex.ToString());
            }
            finally
            {
                GC.Collect();
            }
        } 
    }
}

Solution #1:

This is my way to add data to existing excel file: (Its very simple and efficient)

1 – Add Microsoft.Office.Interop.Excel component as a reference to your application
You can find it in .Net FrameWork in Extensions section

2- then add:

using Excel = Microsoft.Office.Interop.Excel;
using System.Reflection;

3- Now I have a simple class with 3 methods (openExcel, addDataToExcel, closeExcel)

public class ExcelFile
{

    private string excelFilePath = string.Empty;
    private int rowNumber = 1; // define first row number to enter data in excel

    Excel.Application myExcelApplication;
    Excel.Workbook myExcelWorkbook;
    Excel.Worksheet myExcelWorkSheet;

    public string ExcelFilePath
    {
        get { return excelFilePath; }
        set { excelFilePath = value; }
    }

    public int Rownumber
    {
        get { return rowNumber; }
        set { rowNumber = value; }
    }

    public void openExcel()
    {
        myExcelApplication = null;

        myExcelApplication = new Excel.Application(); // create Excell App
        myExcelApplication.DisplayAlerts = false; // turn off alerts


        myExcelWorkbook = (Excel.Workbook)(myExcelApplication.Workbooks._Open(excelFilePath, System.Reflection.Missing.Value,
           System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value,
           System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value,
           System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value,
           System.Reflection.Missing.Value, System.Reflection.Missing.Value)); // open the existing excel file

        int numberOfWorkbooks = myExcelApplication.Workbooks.Count; // get number of workbooks (optional)

        myExcelWorkSheet = (Excel.Worksheet)myExcelWorkbook.Worksheets[1]; // define in which worksheet, do you want to add data
        myExcelWorkSheet.Name = "WorkSheet 1"; // define a name for the worksheet (optinal)

        int numberOfSheets = myExcelWorkbook.Worksheets.Count; // get number of worksheets (optional)
    }

    public void addDataToExcel(string firstname, string lastname, string language, string email, string company)
    {

        myExcelWorkSheet.Cells[rowNumber, "H"] = firstname;
        myExcelWorkSheet.Cells[rowNumber, "J"] = lastname;
        myExcelWorkSheet.Cells[rowNumber, "Q"] = language;
        myExcelWorkSheet.Cells[rowNumber, "BH"] = email;
        myExcelWorkSheet.Cells[rowNumber, "CH"] = company;
        rowNumber++;  // if you put this method inside a loop, you should increase rownumber by one or wat ever is your logic

    }

    public void closeExcel()
    {
        try
        {
            myExcelWorkbook.SaveAs(excelFilePath, System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value,
                                           System.Reflection.Missing.Value, System.Reflection.Missing.Value, Excel.XlSaveAsAccessMode.xlNoChange,
                                           System.Reflection.Missing.Value, System.Reflection.Missing.Value, System.Reflection.Missing.Value,
                                           System.Reflection.Missing.Value, System.Reflection.Missing.Value); // Save data in excel


            myExcelWorkbook.Close(true, excelFilePath, System.Reflection.Missing.Value); // close the worksheet


        }
        finally
        {
            if (myExcelApplication != null)
            {
                myExcelApplication.Quit(); // close the excel application
            }
        }

    }
}
Respondent: Parsa

Solution #2:

According to Programmatically Insert to Existing Excel File using C# by R Manimaran:

Here is the code which will do the insertion in an already exists excel file.

private static Microsoft.Office.Interop.Excel.Workbook mWorkBook;
private static Microsoft.Office.Interop.Excel.Sheets mWorkSheets;
private static Microsoft.Office.Interop.Excel.Worksheet mWSheet1;
private static Microsoft.Office.Interop.Excel.Application oXL;
public static void ReadExistingExcel()
{
   string path = @"C:ToolReports1.xls";
   oXL = new Microsoft.Office.Interop.Excel.Application();
   oXL.Visible = true;
   oXL.DisplayAlerts = false;
   mWorkBook = oXL.Workbooks.Open(path, 0, false, 5, "", "", false, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "", true, false, 0, true, false, false);
   //Get all the sheets in the workbook
  mWorkSheets = mWorkBook.Worksheets;
   //Get the allready exists sheet
   mWSheet1 = (Microsoft.Office.Interop.Excel.Worksheet)mWorkSheets.get_Item("Sheet1");
   Microsoft.Office.Interop.Excel.Range range= mWSheet1.UsedRange;
   int colCount = range.Columns.Count;
   int rowCount= range.Rows.Count;
   for (int index = 1; index < 15; index++)
   {
      mWSheet1.Cells[rowCount + index, 1] = rowCount +index;
      mWSheet1.Cells[rowCount + index, 2] = "New Item"+index;
   }
   mWorkBook.SaveAs(path, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal,
   Missing.Value, Missing.Value, Missing.Value,    Missing.Value,Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive,
   Missing.Value, Missing.Value, Missing.Value,
   Missing.Value, Missing.Value);
   mWorkBook.Close(Missing.Value, Missing.Value, Missing.Value);
   mWSheet1 = null;
   mWorkBook = null;
   oXL.Quit();
   GC.WaitForPendingFinalizers();
   GC.Collect();
   GC.WaitForPendingFinalizers();
   GC.Collect();
} 

If you need to create a new Sheet use the following code.

oSheet = (Excel.Worksheet)oWB.Sheets.Add(Missing.Value, Missing.Value, Missing.Value,      Missing.Value);

oSheet.Name = SheetName;
Respondent: Vignesh Kumar A

Solution #3:

Use ClosedXml dll in my case its resolved my problem

 var workbook = new XLWorkbook(fileName);
  var ws1 = workbook.Worksheet(1);
  var ws2 = workbook.Worksheet(2);
  workBook.SaveAs(fileName);

Here is my code:

public void ExcelDataAssign(List<string> ColumnwiseData, int length, DateTime ReportDate, List<string> AmountList, List<string> PeriodDateList, int CellId)
    {
        int PeriodColIndex = 6, Desc1ColIndex = 14, Desc2ColIndex = 11, Desc3ColIndex = 9, PeriodDateColIndex = 7;
        int PeriodRowIndex = 3, Desc1RowIndex = 1, Desc2RowIndex = 1, Desc3RowIndex = 1, PeriodDateRowIndex = 3;


        string cellName = ColumnwiseData[length];
        string CapitiveName = ColumnwiseData[2 * length];
        string DomicileName = ColumnwiseData[3 * length];


        string file = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location) + @"ExcelOutputTemplate.xlsx";
        string fileName = file.Replace("bin", "").Replace("Debug", "");
        var workbook = new XLWorkbook(fileName);
        var ws1 = workbook.Worksheet(1);

        ws1.Cell(1, 2).Value = DomicileName;
        ws1.Cell(2, 2).Value = CapitiveName;
        ws1.Cell(3, 2).Value = cellName;
        ws1.Cell(4, 2).Value = ReportDate;

        int amntIncr = 0;
        while (AmountList.Count > amntIncr)
        {
            ws1.Cell(PeriodColIndex, PeriodRowIndex).Value = "Period";
            ws1.Cell(Desc1ColIndex, Desc1RowIndex + 2).Value = AmountList[amntIncr];
            ws1.Cell(Desc2ColIndex, Desc2RowIndex + 2).Value = (AmountList[amntIncr + 1]);
            ws1.Cell(Desc3ColIndex, Desc3RowIndex + 2).Value = (AmountList[amntIncr + 2]);
            PeriodRowIndex++;
            Desc1RowIndex++;
            Desc2RowIndex++;
            Desc3RowIndex++;
            amntIncr = amntIncr + 3;

        }
        int periodDateIncr = 0;
        while (PeriodDateList.Count > periodDateIncr)
        {
            ws1.Cell(PeriodDateColIndex, PeriodDateRowIndex).Value = PeriodDateList[periodDateIncr];
            PeriodDateRowIndex++;
            periodDateIncr = periodDateIncr + 3;
        }

        var ws2 = workbook.Worksheet(2);
        ws2.Cell(1, 2).Value = DomicileName;
        ws2.Cell(2, 2).Value = CapitiveName;
        ws2.Cell(3, 2).Value = cellName;
        ws2.Cell(4, 2).Value = ReportDate;


        SqlParameter paramCellId = new SqlParameter("@CellId", CellId);
        SqlParameter paramReportDate = new SqlParameter("@ReportDate", ReportDate);
        DataTable dt = new DataTable();
        var data = SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, "Usp_inputResult", paramCellId, paramReportDate).Tables[0];


        List<string> lstClmwiseData = new List<string>();

        foreach (DataRow r in data.Rows)
        {
            foreach (DataColumn c in data.Columns)
            {
                lstClmwiseData.Add(r[c].ToString());
            }
        }

        int snoColIndex = 6, GLCodeColIndex = 6, DescriptioColIndex = 6, movementDebitColIndex = 6, movementCreditColIndex = 6, ClosingdebitcolIndex = 6, ClosingCreditColIndex = 6;
        int snoRowIndex = 1, GLCodRowIndex = 2, DescriptioRowIndex = 3, movementDebitRowIndex = 4, movementCreditRowIndex = 5, ClosingdebitRowIndex = 6, ClosingCreditRowIndex = 7;
        int secondSheet = 0;
        int SnoIncrement = 1;
        while (lstClmwiseData.Count > secondSheet)
        {
            ws2.Cell(snoColIndex, snoRowIndex).Value = SnoIncrement;
            ws2.Cell(GLCodeColIndex, GLCodRowIndex).Value = lstClmwiseData[secondSheet];
            ws2.Cell(DescriptioColIndex, DescriptioRowIndex).Value = lstClmwiseData[secondSheet + 1];
            ws2.Cell(movementDebitColIndex, movementDebitRowIndex).Value = lstClmwiseData[secondSheet + 2];
            ws2.Cell(movementCreditColIndex, movementCreditRowIndex).Value = lstClmwiseData[secondSheet + 3];
            ws2.Cell(ClosingdebitcolIndex, ClosingdebitRowIndex).Value = lstClmwiseData[secondSheet + 4];
            ws2.Cell(ClosingCreditColIndex, ClosingCreditRowIndex).Value = lstClmwiseData[secondSheet + 5];
            snoColIndex++;
            GLCodeColIndex++;
            DescriptioColIndex++;
            movementDebitColIndex++;
            movementCreditColIndex++;
            ClosingdebitcolIndex++;
            ClosingCreditColIndex++;
            SnoIncrement++;
            secondSheet = secondSheet + 6;

        }
        string path = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile) + @"DownloadsReportUtitlity";
        if (!Directory.Exists(path))
        {
            Directory.CreateDirectory(path);
        }
        string FileName = workbook.Author + "_" + "Report_"+CellId+ "CellId" +"_" + $"{DateTime.Now:yyyy-MM-dd_HH-mm-ss-fff}";
        workbook.SaveAs(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile) + @"DownloadsReportUtitlity"" + FileName + ".xlsx");
    }
Respondent: Grace

The answers/resolutions are collected from stackoverflow, are licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0 .

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