“connection.Close（）”是关闭SQL连接的最佳或最安全的方法吗？

Question

I've been using

connection.Close();

But this is my first project in .NET and I'm not sure if I'm closing it correctly.

I don't want my website to instantly die after putting it out on real hosting.

Usually I do it this way:

    SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());

    SqlCommand cmd = new SqlCommand();

    cmd.Connection = conn;

    // <some code>

    conn.Open();
    / <some code>
    conn.Close();

Answer 1

You should place the connection in a using statement;

using(var connection = new SqlConnection)
{
  connection.Open();
  ...other code using it here.
}

The using statement ensures that the SqlConnection is disposed when you are done with it. In your scenario (depending on where you put the close method), if an exception is closed, it will never reach the Close() method and the connection will stay open.

Even better is that since you are building a website. There should be a method on the Request object (which should be available) called RegisterForDispose. This will automatically Dispose of the connection (which closes it) when the request ends. You can use it like this:

var connection = new SqlConnection();
Request.RegisterForDispose(connection);

Both accomplish the same thing in the end, but the second allows for more flexibility.

Answer 2

Do what Kevin said and put your .Open() call inside the using block:

using(var conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString()))
{
    var cmd = new SqlCommand("my sql command here", conn);

    conn.Open();

    cmd.(whatever method you are using)
}