Mysql连接无法使用"使用"

Question

我正在尝试这个

string query = "SELECT * FROM teams ORDER BY name";

using(MySqlConnection dbConn = new MySqlConnection(conn))
{
    MySqlCommand cmd = new MySqlCommand(query, dbConn);
    MySqlDataReader dataReader = cmd.ExecuteReader();

但它在MysqlCommand行上返回一个错误,说Connection必须有效并且打开.任何人都知道我做错了什么？

Answer 1

你没有打开代码中的连接,你应该打电话

dbConn.Open();

它与using陈述无关.

string query = "SELECT * FROM teams ORDER BY name";
using(MySqlConnection dbConn = new MySqlConnection(conn))
{
    MySqlCommand cmd = new MySqlCommand(query, dbConn);
    dbConn.Open();//here **
    MySqlDataReader dataReader = cmd.ExecuteReader();

using 语句只确保您的连接对象将在范围之后处理,它不会打开连接本身.