GUI Windows Forms C# Tutorial

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Data.Common;
   class Form1 : Form
   {
      private void OnFormLoad(object sender, EventArgs e)
      {
         SqlConnection conn = new SqlConnection("server=localhost;database=Northwind;trusted_connection=true");
         SqlCommand cmd = new SqlCommand("SELECT CustomerID, CompanyName, ContactName, Phone FROM Customers", conn);
         using (conn)
         {
            conn.Open();
            SqlDataReader reader = cmd.ExecuteReader();
            m_CustomersBindingSource.DataSource = reader;
         }
      }
      private void OnGetItem(object sender, EventArgs e)
      {
         int pos;
         bool success = int.TryParse(m_ItemTextBox.Text,out pos);
         if (!success)
         {
            pos = m_CustomersBindingSource.Position;
         }
         DbDataRecord row = m_CustomersBindingSource.List[pos] as DbDataRecord;
         MessageBox.Show("Customer: " + row["CompanyName"]);
      }
      public Form1()
      {
         InitializeComponent();
         m_Grid.AutoGenerateColumns = true;
      }
      private void InitializeComponent()
      {
         this.m_ItemTextBox = new System.Windows.Forms.TextBox();
         this.m_Grid = new System.Windows.Forms.DataGridView();
         this.m_GetItemButton = new System.Windows.Forms.Button();
         this.m_CustomersBindingSource = new System.Windows.Forms.BindingSource();
         ((System.ComponentModel.ISupportInitialize)(this.m_Grid)).BeginInit();
         ((System.ComponentModel.ISupportInitialize)(this.m_CustomersBindingSource)).BeginInit();
         this.SuspendLayout();
         // 
         this.m_ItemTextBox.Location = new System.Drawing.Point(94, 197);
         this.m_ItemTextBox.Name = "m_ItemTextBox";
         this.m_ItemTextBox.Size = new System.Drawing.Size(100, 20);
         this.m_ItemTextBox.TabIndex = 5;
         this.m_ItemTextBox.Text = "0";
         // 
         this.m_Grid.AutoGenerateColumns = false;
         this.m_Grid.DataSource = this.m_CustomersBindingSource;
         this.m_Grid.Location = new System.Drawing.Point(12, 12);
         this.m_Grid.Name = "m_Grid";
         this.m_Grid.Size = new System.Drawing.Size(465, 176);
         this.m_Grid.TabIndex = 4;
         // 
         this.m_GetItemButton.Location = new System.Drawing.Point(12, 195);
         this.m_GetItemButton.Name = "m_GetItemButton";
         this.m_GetItemButton.Size = new System.Drawing.Size(75, 23);
         this.m_GetItemButton.TabIndex = 3;
         this.m_GetItemButton.Text = "Get Item:";
         this.m_GetItemButton.Click += new System.EventHandler(this.OnGetItem);
         // 
         this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
         this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
         this.ClientSize = new System.Drawing.Size(503, 232);
         this.Controls.Add(this.m_ItemTextBox);
         this.Controls.Add(this.m_Grid);
         this.Controls.Add(this.m_GetItemButton);
         this.Name = "Form1";
         this.Text = "Form1";
         this.Load += new System.EventHandler(this.OnFormLoad);
         ((System.ComponentModel.ISupportInitialize)(this.m_Grid)).EndInit();
         ((System.ComponentModel.ISupportInitialize)(this.m_CustomersBindingSource)).EndInit();
         this.ResumeLayout(false);
         this.PerformLayout();
      }
      private System.Windows.Forms.TextBox m_ItemTextBox;
      private System.Windows.Forms.DataGridView m_Grid;
      private System.Windows.Forms.Button m_GetItemButton;
      private System.Windows.Forms.BindingSource m_CustomersBindingSource;
      [STAThread]
      static void Main()
      {
         Application.EnableVisualStyles();
         Application.Run(new Form1());
      }
   }