Working with Disconnected Data - The DataSet and SqlDataAdapter (c#)

Listing 1: Implementing a Disconnected Data Management Strategy

using System;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Windows.Forms;

class DisconnectedDataform : Form
{
 private SqlConnection  conn;
 private SqlDataAdapter daCustomers;

 private DataSet  dsCustomers;
 private DataGrid dgCustomers;

 private const string tableName = "Customers";

 // initialize form with DataGrid and Button
 public DisconnectedDataform()
 {
  // fill dataset
  Initdata();

 // set up datagrid
 dgCustomers = new DataGrid();
 dgCustomers.Location = new Point(5, 5);
 dgCustomers.Size = new Size(  
        this.ClientRectangle.Size.Width - 10,  
        this.ClientRectangle.Height - 50);
        dgCustomers.DataSource = dsCustomers;
        dgCustomers.DataMember = tableName;

 // create update button
 Button btnUpdate = new Button();
 btnUpdate.Text = "Update";
 btnUpdate.Location = new Point(
        this.ClientRectangle.Width/2 - btnUpdate.Width/2,
 this.ClientRectangle.Height - (btnUpdate.Height + 10));
 btnUpdate.Click += new EventHandler(btnUpdateClicked);

 // make sure controls appear on form
 Controls.AddRange(new Control[] { dgCustomers, btnUpdate });
 }

 // set up ADO.NET objects
 public void Initdata()
 {
  // instantiate the connection
  conn = new SqlConnection(
 "Server=(local);DataBase=Northwind;Integrated Security=SSPI");
  
 // 1. instantiate a new DataSet
 dsCustomers = new DataSet();

 // 2. init SqlDataAdapter with select command and connection
 daCustomers = new SqlDataAdapter(
  "select CustomerID, CompanyName from Customers", conn);

 // 3. fill in insert, update, and delete commands
 SqlCommandBuilder cmdBldr = new SqlCommandBuilder(daCustomers);
  
 // 4. fill the dataset
 daCustomers.Fill(dsCustomers, tableName);
 }

 // Update button was clicked
 public void btnUpdateClicked(object sender, EventArgs e)
 {
  // write changes back to DataBase
  daCustomers.Update(dsCustomers, tableName);
 }

 // start the Windows form
 static void Main()
 {
  Application.Run(new DisconnectedDataForm());
 }
 }