How to import all the Excel sheets to DataSet in C#

This is a code I came up with and it works perfect but I saw someone else already added an answer:

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;
}