Error “There is already an open DataReader associated with this Command which must be closed first” when using 2 distinct commands

Question

I have this legacy code :

 private void conecta()
 {  
     if (conexao.State == ConnectionState.Closed)
         conexao.Open();
 }

 public List

        

Answer 1

I suggest creating an additional connection for the second command, would solve it. Try to combine both queries in one query. Create a subquery for the count.

while (dr3.Read())
{
    dados_historico[4] = dr3["QT"].ToString(); //quantidade de emails lidos naquela verificação
}

Why override the same value again and again?

if (dr3.Read())
{
    dados_historico[4] = dr3["QT"].ToString(); //quantidade de emails lidos naquela verificação
}

Would be enough.