C#

Luc Pattyn wrote:

would ... not be absolutely equivalent?

SELECT A,B,C FROM ...

SELECT B,A,C FROM ...

Luc Pattyn wrote:

Would it also negatively affect performance?

int customerId = reader.GetOrdinal("CustomerID");
int customerName = reader.GetOrdinal("Name");
while (reader.Read())
{
  Customer cust = new Customer(GetValue(reader, customerId), GetValue(reader, customerName));
}

private T GetValue(SqlDataReader dr, int position)
{
  if (dr.IsDbNull(position))
    return default(T);
  return (T)dr[position];
}

Luc Pattyn wrote:

The rule now is: don't use numeric field indexes ever; use field names directly,
unless you can't afford the speed penalty, then use GetOrdinal as per your
example (which is safe but somewhat more verbose).

private void MyComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
	MyGoupbox.Enabled == (MyComboBox.SelectedValue == criteria);
}

public Form1()
       {
           InitializeComponent();
       }

       public void Hello(string name)
       {
           MessageBox.Show(string.Format("Hello, {0}", name)
       }

public partial class Form2 : Form
    {
        Form1 form1;

        public Form2()
        {
            InitializeComponent();
            form1 = new Form1();
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            form1.Hello("Wayne");
        }
    }

public static void Hola()
{
     MessageBox.Show("Hello");
}

public void InvokeMessage()
{
     Form1.Hola();
}

public void InvokeMessage()
{
     // "using" so Form1 is disposed at end of method.
     using(Form1 otherForm = new Form1())
     {
          otherForm.Hola();
     }
}