以下两个例子哪一个是正确的?(或者哪一个更好,我应该使用哪一个)
在 MSDN 中我找到了这个:
private static void ReadOrderData(string connectionString)
{
string queryString = "SELECT OrderID, CustomerID FROM dbo.Orders;"
using (SqlConnection connection = new SqlConnection(connectionString))
{
SqlCommand command = new SqlCommand(queryString, connection);
connection.Open();
SqlDataReader reader = command.ExecuteReader();
// Call Read before accessing data.
while (reader.Read())
{
Console.WriteLine(String.Format("{0}, {1}", reader[0], reader[1]));
}
// Call Close when done reading.
reader.Close();
}
}
然而,在查看其他页面时,一些用户建议使用以下方法:
private static void ReadOrderData(string connectionString)
{
string queryString = "SELECT OrderID, CustomerID FROM dbo.Orders;";
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlCommand command = new SqlCommand(queryString, connection))
{
connection.Open();
using (SqlDataReader reader = command.ExecuteReader())
{
// Call Read before accessing data.
while (reader.Read())
{
Console.WriteLine(String.Format("{0}, {1}", reader[0], reader[1]));
}
}
}
}
}
那么问题是:我是否应该在SqlCommand
和SqlDataReader
中也使用using
语句,或者它们会在SqlConnection
using
代码块结束时自动被处理。