我在这段代码中有两个DataReader，vs给我这个错误＆＃34;连接没有关闭。连接的当前状态是开放的。＆＃34;错误来自connection2。我查看我的代码，但我的两个连接已关闭。问题出在哪里？
protected void Page_Load(object sender, EventArgs e)
{
using (SqlConnection connection1 = DBConnection.getConnection())
{
string strquery1 = " with distinctvalueyes (typearticle) as (select top 1 'Fruit' FROM WeedingSalonGeneralRes where Fruit=1 union all select top 1 'Drink' FROM WeedingSalonGeneralRes where Drink=1 union all select top 1 'Desert' FROM WeedingSalonGeneralRes where Desert=1 union all select top 1 'MainFood' FROM WeedingSalonGeneralRes where MainFood=1 union all select top 1 'Salad' FROM WeedingSalonGeneralRes where Salad=1 union all select top 1 'TableFlower' FROM WeedingSalonGeneralRes where TableFlower=1 union all select top 1 'SaloonLighting' FROM WeedingSalonGeneralRes where SaloonLighting=1 union all select top 1 'Saloondesign' FROM WeedingSalonGeneralRes where Saloondesign=1 union all select top 1 'SloonCrew' FROM WeedingSalonGeneralRes where SloonCrew=1 union all select top 1 'Pastry' FROM WeedingSalonGeneralRes where Pastry=1 union all select top 1 'GiftCard' FROM WeedingSalonGeneralRes where GiftCard=1 ) select * from distinctvalueyes ";
connection1.Open();
SqlCommand cmd1 = new SqlCommand();
cmd1.Connection = connection1;
cmd1.CommandText = strquery1;
string cis = Session["customerID"].ToString();
lbl2_customerid.Text = cis;
SqlDataReader reader = cmd1.ExecuteReader();
if (reader.Read())
{
lbl8_fruit.Text = reader[0].ToString();
// wrapped in a using block, connection will now always be closed and disposed
using (SqlConnection connection2 = DBConnection.getConnection())
{
//query for fetch service prices
string strquery2 = "SELECT Fruit_price,Drink_price,Desert_price,MainFood_price,Salad_price,TableFlower_price,SaloonLighting_price,SaloonDesign_price,SaloonCrew_price,Pastry_price,GiftCard_price FROM GenReservationServicePrice";
connection2.Open();
SqlCommand cmd2 = new SqlCommand();
cmd2.Connection = connection2;
cmd2.CommandText = strquery2;
SqlDataReader reader2 = cmd2.ExecuteReader();
if (reader2.Read())
{
string Fruit_price;
string Drink_price;
string Desert_price;
string MainFood_price;
string Salad_price;
string TableFlower_price;
string SaloonLighting_price;
string SaloonDesign_price;
string SaloonCrew_price;
string Pastry_price;
string GiftCard_price;
Fruit_price = reader[0].ToString();
Drink_price = reader[1].ToString();
Desert_price = reader[2].ToString();
MainFood_price = reader[3].ToString();
Salad_price = reader[4].ToString();
TableFlower_price = reader[5].ToString();
SaloonLighting_price = reader[6].ToString();
SaloonDesign_price = reader[7].ToString();
SaloonCrew_price = reader[8].ToString();
Pastry_price = reader[9].ToString();
GiftCard_price = reader[10].ToString();
lbl8_fruit.Text = Fruit_price;
}
}
}
}
}
///connection class
public class DBConnection
{
private static SqlConnection connection=null;
public DBConnection()
{
}
public static SqlConnection getConnection()
{
if (connection != null)
{ return connection; }
else
{
String connectionString = WebConfigurationManager.AppSettings["connectionString"];
connection = new SqlConnection(connectionString);
return connection;
}
}
}
答案 0 :(得分：0)
问题是你试图在2个地方使用相同的SqlConnection实例。每次需要时，您应该使用新的SqlConnection。
代码更改：
///connection class
public class DBConnection
{
public static SqlConnection getConnection()
{
String connectionString = WebConfigurationManager.AppSettings["connectionString"];
return new SqlConnection(connectionString);
}
}
Sql Server有一个名为Connection Pooling的东西，默认情况下启用它。在c＃中创建连接会重用Sql Server上已有的连接，因此这个操作非常便宜。包含使用SqlConnections块中using的所有代码，以确保它们始终处于关闭状态，因此您没有连接泄漏。
app.config / web.config也有一个ConnectionString section。您应该使用它而不是应用程序设置。
您应该将所有SqlConnection个实例包装在using块中。这将确保即使发生异常，也始终关闭和释放连接。它也可以完成代码中的所有检查工作，无需查看它是否在关闭时打开。
以下是您使用using块更改的代码，我删除了一些逻辑，因此很清楚我所做的更改。
protected void Page_Load(object sender, EventArgs e)
{
/* your existing code removed for clarit */
// wrapped in a using block, connection will now always be closed and disposed
using(SqlConnection connection1 = DBConnection.getConnection())
{
connection1.Open();
SqlCommand cmd1 = new SqlCommand();
cmd1.Connection = connection1;
cmd1.CommandText = strquery1;
string cis = Session["customerID"].ToString();
lbl2_customerid.Text = cis;
SqlDataReader reader = cmd1.ExecuteReader();
if (reader.Read())
{
/* your existing code removed for clarit */
// wrapped in a using block, connection will now always be closed and disposed
using(SqlConnection connection2 = DBConnection.getConnection())
{
connection2.Open();
SqlCommand cmd2 = new SqlCommand();
cmd2.Connection = connection2;
cmd2.CommandText = strquery2;
SqlDataReader reader2 = cmd2.ExecuteReader();
if (reader2.Read())
{
/* your existing code removed for clarit */
}
}
}
}
}