Question

我会做出这件事：

"select nome,cognome from Utenti where CodiceCliente = @codice"

然后使用“nome”中的值和后面代码中“cognome”中的值。在PHP中有关联数组，在C＃ASP.NET中？ “直到现在我总是使用两种不同的命令，但现在它很烦人例如：

MySqlCommand getNome = new MySqlCommand("select Nome from Utenti where CodiceCliente = @codice", userConnection);
    MySqlCommand getCognome = new MySqlCommand("select Cognome from Utenti where CodiceCliente = @codice", userConnection);
    MySqlCommand getEmail = new MySqlCommand("select IndirizzoEmail from Utenti where CodiceCliente = @codice", userConnection);
    getNome.Parameters.AddWithValue("@codice", codice);
    getCognome.Parameters.AddWithValue("@codice", codice);
    getEmail.Parameters.AddWithValue("@codice", codice);
    userConnection.Open();
    string nome = Convert.ToString(getNome.ExecuteScalar());
    string cognome = Convert.ToString(getCognome.ExecuteScalar());
    string email = Convert.ToString(getEmail.ExecuteScalar());

你能帮助我吗？在此之前，谢谢丹尼尔

Answer 1

简单用法：

using(var connection = new MySqlConnection(myConnString))
{
   var cmd = connection.CreateCommand();
   cmd.CommandText = "select nome,cognome from Utenti where CodiceCliente = @codice";
   cmd.Parameters.AddWithValue("@codice", value);
   var reader = cmd.ExecuteReader();
   while(reader.Read())
   {
       // here could be problems if database value is null
       var nome = reader["nome"];
       var cognome = reader["cognome"];
   }
}

Answer 2

你可以试试这个：

using(var connection = new MySqlConnection(myConnString))
{
   var cmd = connection.CreateCommand();
   cmd.CommandText = "select nome,cognome from Utenti where CodiceCliente = @codice";
   cmd.Parameters.AddWithValue("@codice", value);
   var reader = cmd.ExecuteReader();
  if(reader.HasRows) {
   while(reader.Read())
   {

       var nome = reader[0];
       var cognome = reader[1];
   }
reader.Close();
}
}

您必须检查DataReader是否有行以避免异常，最后不要忘记关闭

C＃ASP.NET从同一个mysql命令中选择多个列并在后面的代码中使用它们

2 个答案: