Demande explication

Bonjour,
public static QuizInfo GetQuiz(int quizId)
{
QuizInfo quiz=null;
string queryString="QuizGet";
{
SqlDataReader reader;
using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlCommand command =
new SqlCommand(queryString, connection);
command.CommandType=CommandType.StoredProcedure;
SqlParameter quizID= new SqlParameter("@quizID", SqlDbType.Int, 4);
quizID.Value=quizId;
command.Parameters.Add(quizID);
connection.Open();
reader = command.ExecuteReader();

while (reader.Read() && reader.HasRows==true )

{
quiz=new QuizInfo(int.Parse(reader.GetValue(0).ToString()), reader.GetValue(1).ToString() ,int.Parse( reader.GetValue(2).ToString()) , reader.GetValue(3).ToString() ,reader.GetValue(4).ToString() ,reader.GetValue(5).ToString() , reader.GetValue(6).ToString() , reader.GetValue(7).ToString() , reader.GetValue(8).ToString() , reader.GetValue(9).ToString() ,DateTime.Parse(reader.GetValue(10).ToString()),DateTime.Parse(reader.GetValue(11).ToString()) ,float.Parse(reader.GetValue(12).ToString()) ,int.Parse(reader.GetValue(13).ToString()) ,float.Parse(reader.GetValue(14).ToString()));

}
reader.Close();
return quiz;
}
}
}

je voudrais une explication detaillet SVP j'en é besoin le plus vite possible
merci .