[c#] Is there any simple way to convert .xls file to .csv file? (Excel)

Is there any simple way to convert .xls file to .csv file ? (Excel)

in C# code ?

i mean to take an existing .xls file and convert them to .csv file

Thanks in advance

Checkout the .SaveAs() method in Excel object.

wbWorkbook.SaveAs("c:\yourdesiredFilename.csv", Microsoft.Office.Interop.Excel.XlFileFormat.xlCSV)

Or following:

public static void SaveAs()
{
    Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.ApplicationClass();
    Microsoft.Office.Interop.Excel.Workbook wbWorkbook = app.Workbooks.Add(Type.Missing);
    Microsoft.Office.Interop.Excel.Sheets wsSheet = wbWorkbook.Worksheets;
    Microsoft.Office.Interop.Excel.Worksheet CurSheet = (Microsoft.Office.Interop.Excel.Worksheet)wsSheet[1];

    Microsoft.Office.Interop.Excel.Range thisCell = (Microsoft.Office.Interop.Excel.Range)CurSheet.Cells[1, 1];

    thisCell.Value2 = "This is a test.";

    wbWorkbook.SaveAs(@"c:\one.xls", Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlShared, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
    wbWorkbook.SaveAs(@"c:\two.csv", Microsoft.Office.Interop.Excel.XlFileFormat.xlCSVWindows, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlShared, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

    wbWorkbook.Close(false, "", true);
}

I need to do the same thing. I ended up with something similar to Kman

       static void ExcelToCSVCoversion(string sourceFile,  string targetFile)
    {
        Application rawData = new Application();

        try
        {
            Workbook workbook = rawData.Workbooks.Open(sourceFile);
            Worksheet ws = (Worksheet) workbook.Sheets[1];
            ws.SaveAs(targetFile, XlFileFormat.xlCSV);
            Marshal.ReleaseComObject(ws);
        }

        finally
        {
            rawData.DisplayAlerts = false;
            rawData.Quit();
            Marshal.ReleaseComObject(rawData);
        }


        Console.WriteLine();
        Console.WriteLine($"The excel file {sourceFile} has been converted into {targetFile} (CSV format).");
        Console.WriteLine();
    }

If there are multiple sheets this is lost in the conversion but you could loop over the number of sheets and save each one as csv.

This is a modification of nate_weldon's answer with a few improvements:

• More robust releasing of Excel objects
• Set application.DisplayAlerts = false; before attempting to save to hide prompts

Also note that the application.Workbooks.Open and ws.SaveAs methods expect sourceFilePath and targetFilePath to be full paths (ie. directory path + filename)

private static void SaveAs(string sourceFilePath, string targetFilePath)
{
    Application application = null;
    Workbook wb = null;
    Worksheet ws = null;

    try
    {
        application = new Application();
        application.DisplayAlerts = false;
        wb = application.Workbooks.Open(sourceFilePath);
        ws = (Worksheet)wb.Sheets[1];
        ws.SaveAs(targetFilePath, XlFileFormat.xlCSV);
    }
    catch (Exception e)
    {
        // Handle exception
    }
    finally
    {
        if (application != null) application.Quit();
        if (ws != null) Marshal.ReleaseComObject(ws);
        if (wb != null) Marshal.ReleaseComObject(wb);
        if (application != null) Marshal.ReleaseComObject(application);
    }
}

I integrate the @mattmc3 aswer. If you want to convert a xlsx file you should use this connection string (the string provided by matt works for xls formats, not xlsx):

var cnnStr = String.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=\"Excel 12.0;IMEX=1;HDR=NO\"", excelFilePath);

Here's a C# method to do this. Remember to add your own error handling - this mostly assumes that things work for the sake of brevity. It's 4.0+ framework only, but that's mostly because of the optional worksheetNumber parameter. You can overload the method if you need to support earlier versions.

static void ConvertExcelToCsv(string excelFilePath, string csvOutputFile, int worksheetNumber = 1) {
   if (!File.Exists(excelFilePath)) throw new FileNotFoundException(excelFilePath);
   if (File.Exists(csvOutputFile)) throw new ArgumentException("File exists: " + csvOutputFile);

   // connection string
   var cnnStr = String.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties=\"Excel 8.0;IMEX=1;HDR=NO\"", excelFilePath);
   var cnn = new OleDbConnection(cnnStr);

   // get schema, then data
   var dt = new DataTable();
   try {
      cnn.Open();
      var schemaTable = cnn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
      if (schemaTable.Rows.Count < worksheetNumber) throw new ArgumentException("The worksheet number provided cannot be found in the spreadsheet");
      string worksheet = schemaTable.Rows[worksheetNumber - 1]["table_name"].ToString().Replace("'", "");
      string sql = String.Format("select * from [{0}]", worksheet);
      var da = new OleDbDataAdapter(sql, cnn);
      da.Fill(dt);
   }
   catch (Exception e) {
      // ???
      throw e;
   }
   finally {
      // free resources
      cnn.Close();
   }

   // write out CSV data
   using (var wtr = new StreamWriter(csvOutputFile)) {
      foreach (DataRow row in dt.Rows) {
         bool firstLine = true;
         foreach (DataColumn col in dt.Columns) {
            if (!firstLine) { wtr.Write(","); } else { firstLine = false; }
            var data = row[col.ColumnName].ToString().Replace("\"", "\"\"");
            wtr.Write(String.Format("\"{0}\"", data));
         }
         wtr.WriteLine();
      }
   }
}

Install these 2 packages

<packages>
  <package id="ExcelDataReader" version="3.3.0" targetFramework="net451" />
  <package id="ExcelDataReader.DataSet" version="3.3.0" targetFramework="net451" />
</packages>

Helper function

using ExcelDataReader;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ExcelToCsv
{
    public class ExcelFileHelper
    {
        public static bool SaveAsCsv(string excelFilePath, string destinationCsvFilePath)
        {

            using (var stream = new FileStream(excelFilePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
            {
                IExcelDataReader reader = null;
                if (excelFilePath.EndsWith(".xls"))
                {
                    reader = ExcelReaderFactory.CreateBinaryReader(stream);
                }
                else if (excelFilePath.EndsWith(".xlsx"))
                {
                    reader = ExcelReaderFactory.CreateOpenXmlReader(stream);
                }

                if (reader == null)
                    return false;

                var ds = reader.AsDataSet(new ExcelDataSetConfiguration()
                {
                    ConfigureDataTable = (tableReader) => new ExcelDataTableConfiguration()
                    {
                        UseHeaderRow = false
                    }
                });

                var csvContent = string.Empty;
                int row_no = 0;
                while (row_no < ds.Tables[0].Rows.Count)
                {
                    var arr = new List<string>();
                    for (int i = 0; i < ds.Tables[0].Columns.Count; i++)
                    {
                        arr.Add(ds.Tables[0].Rows[row_no][i].ToString());
                    }
                    row_no++;
                    csvContent += string.Join(",", arr) + "\n";
                }
                StreamWriter csv = new StreamWriter(destinationCsvFilePath, false);
                csv.Write(csvContent);
                csv.Close();
                return true;
            }
        }
    }
}

Usage :

var excelFilePath = Console.ReadLine();
string output = Path.ChangeExtension(excelFilePath, ".csv");
ExcelFileHelper.SaveAsCsv(excelFilePath, output);