How to upload excel fle to database

using System.IO;
using System.Data;
using System.Data.OleDb;
using System.Data.SqlClient;
using System.Configuration;

 protected void Button1_Click(object sender, EventArgs e)
    {
        //Upload and save the file
        string excelPath = Server.MapPath("~/Files/") + Path.GetFileName(FileUpload1.PostedFile.FileName);
        FileUpload1.SaveAs(excelPath);

        string conString = string.Empty;
        string extension = Path.GetExtension(FileUpload1.PostedFile.FileName);
        switch (extension)
        {
            case ".xls": //Excel 97-03
                conString = ConfigurationManager.ConnectionStrings["Excel03ConString"].ConnectionString;
                break;
            case ".xlsx": //Excel 07 or higher
                conString = ConfigurationManager.ConnectionStrings["Excel07+ConString"].ConnectionString;
                break;

        }
        conString = string.Format(conString, excelPath);
        using (OleDbConnection excel_con = new OleDbConnection(conString))
        {
            excel_con.Open();
            string sheet1 = excel_con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null).Rows[0]["TABLE_NAME"].ToString();
            DataTable dtExcelData = new DataTable();

            //[OPTIONAL]: It is recommended as otherwise the data will be considered as String by default.
            dtExcelData.Columns.AddRange(new DataColumn[2] { new DataColumn("Id", typeof(int)),
                new DataColumn("Name", typeof(string)) });

            using (OleDbDataAdapter oda = new OleDbDataAdapter("SELECT * FROM [" + sheet1 + "]", excel_con))
            {
                oda.Fill(dtExcelData);
            }
            excel_con.Close();

            string consString = ConfigurationManager.ConnectionStrings["dbcn"].ConnectionString;
            using (SqlConnection con = new SqlConnection(consString))
            {
                using (SqlBulkCopy sqlBulkCopy = new SqlBulkCopy(con))
                {
                    //Set the database table name
                    sqlBulkCopy.DestinationTableName = "dbo.Table1";

                    //[OPTIONAL]: Map the Excel columns with that of the database table
                    sqlBulkCopy.ColumnMappings.Add("Sl", "Id");
                    sqlBulkCopy.ColumnMappings.Add("Name", "Name");
                    con.Open();
                    sqlBulkCopy.WriteToServer(dtExcelData);
                    con.Close();
                }
            }
        }
    }

In web config

<add name="Excel03ConString" connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties='Excel 8.0;HDR=YES'"/>
    <add name="Excel07+ConString" connectionString="Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties='Excel 8.0;HDR=YES'"/>