C# Using SQL Method needs a close-method?

Question

When using a using block for SQL connections in C#, does this also a close method? I'm asking as I need to explicitly use the con.Open() method. I found this example:

using (SqlConnection con = new SqlConnection(connectionString))
{
   con.Open(); // open method

   string queryString = "select * from db";
   SqlCommand cmd = new SqlCommand(queryString, con);
   SqlDataReader reader = cmd.ExecuteReader();
   reader.Read();

   ???         // What about a close method?
}

Or does the using block close the connection itself?

Answer 1

using translates to:

SqlConnection con = new SqlConnection(connectionString)
try
{
   con.Open(); <-- open method

   string queryString = "select * from db";
   SqlCommand cmd = new SqlCommand(queryString, con);
   SqlDataReader reader = cmd.ExecuteReader();
   reader.Read();
}
finally
{
    if (con!= null)
        ((IDisposable)con).Dispose();
}

where ((IDisposable)con.Dispose(); closes what is to be closed.