---
title: "Writing Data to an Existing Excel File in C#"  
description: "Writing Data to an Existing Excel File in C#"  
author: "Anonymous User"  
published: 2014-12-18  
updated: 2014-12-19  
canonical: https://www.mindstick.com/forum/12793/writing-data-to-an-existing-excel-file-in-c-sharp  
category: "asp.net"  
tags: ["c#", "excel"]  
reading_time: 3 minutes  

---

# Writing Data to an Existing Excel File in C#

i want to write [data](https://www.mindstick.com/articles/13050/salesforce-aiming-to-dominate-predictive-analytics-with-data-science) to existing [excel](https://www.mindstick.com/articles/12937/how-to-import-excel-data-in-sql-server-2014) [file](https://www.mindstick.com/articles/59/encrypting-and-decrypting-files-using-c-sharp). the file have sheet1, i want to write on sheet2, then save. the [problem](https://yourviews.mindstick.com/view/81399/tackling-the-problem-of-unemployment-during-corona-pandemic) is that every time i save it will create a new excel file and overwrite the [existing one](https://www.mindstick.com/interview/34109/how-do-you-generate-a-unique-file-name-to-avoid-overwriting-an-existing-one). any help to keep the old data while saving.

**I have the following [function](https://www.mindstick.com/articles/13001/multi-statement-table-valued-user-defined-function-in-sql-server)**

```
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, "\t", 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();            }        }     }}
```

## Replies

### Reply by Jayden Bell

```
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            }        }    }}
```

### Reply by Manoj Bhatt

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:\Tool\Reports1.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;


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Original Source: https://www.mindstick.com/forum/12793/writing-data-to-an-existing-excel-file-in-c-sharp

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