How to import data from excel in Asp.net

Call this function:-

private void ImportExcel(Label lbl)

    {

        string connectionString = "";

        string strFileType = Path.GetExtension(fu_excel_N.FileName).ToLower();

        string path = fu_excel_N.PostedFile.FileName;

        if (strFileType.Trim() == ".xlsx")

        {

            connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + FileToConvert + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";

        }

        try

        {

            OleDbConnection connection = new OleDbConnection(connectionString);

            if (connection.State == ConnectionState.Closed)

                connection.Open();

            OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", connection);

            DataSet ds = new DataSet();

            DataTable dt = new DataTable();

            adapter.Fill(ds);

            dt = ds.Tables[0];

            System.Web.HttpContext.Current.Session["ImportExcel"] = dt;

            connection.Close();

            int number_of_columns = dt.Columns.Count;

            string[] columnNames = new string[number_of_columns];

            for (int j = 0; j < number_of_columns; j++)

            {

                columnNames[j] = dt.Columns[j].ToString();

            }

           

        }

        catch (Exception ex)

        {

            lbl.Text = "Error loading file !!!, Make sure that the file is in '.xlsx' format";

            lbl.Visible = true;

            lbl.ForeColor = System.Drawing.Color.Red;

            return;

        }

    }