C# Excel을 DataSet으로 가져오기(클라이언트는 Office를 설치할 필요가 없음)

static DataSet Parse(string fileName)
        {
            string connectionString = string.Format("provider=Microsoft.Jet.OLEDB.4.0; data source={0};Extended Properties=Excel 8.0;", fileName);


            DataSet data = new DataSet();

            foreach (var sheetName in GetExcelSheetNames(connectionString))
            {
                using (OleDbConnection con = new OleDbConnection(connectionString))
                {
                    var dataTable = new DataTable();
                    string query = string.Format("SELECT * FROM [{0}]", sheetName);
                    con.Open();
                    OleDbDataAdapter adapter = new OleDbDataAdapter(query, con);
                    adapter.Fill(dataTable);
                    data.Tables.Add(dataTable);
                }
            }
            return data;        
        }

        static string[] GetExcelSheetNames(string connectionString)
        {
            OleDbConnection con = null;
            DataTable dt = null;
            con = new OleDbConnection(connectionString);
            con.Open();
            dt = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);

            if (dt == null)
            {
                return null;
            }

            String[] excelSheetNames = new String[dt.Rows.Count];
            int i = 0;

            foreach (DataRow row in dt.Rows)
            {
                excelSheetNames[i] = row["TABLE_NAME"].ToString();
                i++;
            }

            return excelSheetNames;
        }