Best way to update quantity from Shopping Basket Screen?

Hi Guys,

I've nearly finished a shopping cart i've been working on but I am having a problem with how best to go about allowing the user to update the quantity of a particular item, the rest of the functionality is present. Just need some help with this as I am stumped.

The code that renders the page that shows the user the basket looks like this:

  private void showItems(int order)
{

string connstring = @"Data Source=xxx.xx.xx.xx;Initial Catalog=x; User ID=x; Password=x;";

SqlConnection conn = new SqlConnection(connstring);
conn.Open();

string sqlLoad = "SELECT * FROM sales WHERE orderid ='" + order + "'";

SqlCommand ...