C#连接MySQL数据库，提示Connection must be valid and open

Question

我的代码如下：           

            MySqlConnectionStringBuilder builder = new MySqlConnectionStringBuilder();
            builder.UserID = "root";
            //密码
            builder.Password = "****";
            //服务器地址
            builder.Server = "localhost";
            //连接时的数据库
            builder.Database = "login";

            MySqlConnection msc = new MySqlConnection(builder.ConnectionString);

           try
            {
                msc.Open();
                Console.WriteLine("lianjiechenggong");
            }
            catch(Exception e)
            {
                Console.WriteLine(e.ToString());
            }

            string sql = "select * from userdate";
            MySqlCommand cmd = new MySqlCommand(sql, msc);
            MySqlDataReader reader = cmd.ExecuteReader();//这里提示:“Connection must be 
            valid and open.”

            while (reader.Read())
            {
                Console.WriteLine(reader[0].ToString() + reader[1].ToString());
            }
            msc.Close();

 

我的数据库叫login，表叫userdate，里面就一条测试数据，这个连接问题请问怎么解决？

 

Answer 1

connectionString="server=192.168.1.100;port=3306;user id=root;password=123456;database=login";
MySqlConnection con = new MySqlConnection(connectionString);
        MySqlCommand cmd = con.CreateCommand();
        MySqlDataAdapter sda = new MySqlDataAdapter();
        DataSet ds = new DataSet();
        try
        {
            con.Open();
            cmd.CommandText = "select * from userdate";
            sda.SelectCommand = cmd;
            sda.Fill(ds, tableName);
        }
        catch (MySqlException ex)
        {
            throw ex;
        }
        finally
        {
            cmd.Dispose();
            sda.Dispose();
            con.Close();
        }
        return ds;