invalid attempt to access a field before calling read() c#

Question

connection.Close();

connection.Open();

cmd = new MySqlCommand("select attend from credit_purchase where date='" + date + "'", connection);

dread = cmd.ExecuteReader();

while (dread.Read())

{

x = dread.GetValue(0).ToString();//this line to error

}

dread.close(); 

connection.close();