How to import an Excel file into DataSet/DataTable from client.

The following lines of code illustrate simple way of importing and .xls file using OLE Jet engine:

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Data;
using System.Data.OleDb;
using System.Xml;
using System.Web;
 
namespace ConvertToExcel {
    public class ExcelImport {
        public static DataSet ImportExcelXLS(HttpPostedFile file, bool hasHeaders) {
            string fileName = Path.GetTempFileName();
            file.SaveAs(fileName);
 
            return ImportExcelXLS(fileName, hasHeaders);
        }
        private static DataSet ImportExcelXLS(string FileName, bool hasHeaders) {
            string HDR = hasHeaders ? "Yes" : "No";
            string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + FileName + ";Extended Properties=\"Excel 8.0;HDR=" + HDR + ";IMEX=1\"";
 
            DataSet output = new DataSet();
 
            using (OleDbConnection conn = new OleDbConnection(strConn)) {
                conn.Open();
 
                DataTable dt = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });
 
                foreach (DataRow row in dt.Rows) {
                    string sheet = row["TABLE_NAME"].ToString();
 
                    OleDbCommand cmd = new OleDbCommand("SELECT * FROM [" + sheet + "]", conn);
                    cmd.CommandType = CommandType.Text;
 
                    DataTable outputTable = new DataTable(sheet);
                    output.Tables.Add(outputTable);
                    new OleDbDataAdapter(cmd).Fill(outputTable);
                }
            }
            return output;
        }
    }
}