Beginning Web Development, Silverlight, and ASP.NET AJAX

88
CHAPTER 4 ■ DATA BINDING WITH ASP.NET
In the next section, you’ll see how to use this reader to step through the results of the
query and access the first line of the returned addresses.
Reading the Data
When you execute the previous command, ADO.NET returns a SqlDataReader. This reader
is a forward-based read-only cursor that moves forward by one record every time you call
its Read method. The Read method returns True if it reads a record and False otherwise.
Upon a successful read, it will then load an array of values with the index of the array representing
the column name—so reader["ColumnName"] will contain this record’s value for
ColumnName.
Thus, we can iterate through the returned result set using a while loop, and upon a
successful read, retrieve the result set’s data by simply accessing the reader as if it were an
array.
Listing 4-1 contains the complete code to access the addresses for postal code 98011
in the AdventureWorks database.
Listing 4-1. Using Connection, Command, and Reader to Access Data
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Web.Configuration;
using System.Data.SqlClient;
using System.Text;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string connectionString =
WebConfigurationManager.ConnectionStrings["AW"].ConnectionString;
StringBuilder strReturn = new StringBuilder();
using (SqlConnection sqlCon = new SqlConnection(connectionString))
{
SqlCommand sqlComm = new SqlCommand();