GUI Windows Form C#

/*
Professional Windows GUI Programming Using C#
by Jay Glynn, Csaba Torok, Richard Conway, Wahid Choudhury, 
   Zach Greenvoss, Shripad Kulkarni, Neil Whitlow
Publisher: Peer Information
ISBN: 1861007663
*/
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
namespace UpDown
{
    /// 
    /// Summary description for UpDown.
    /// 

    public class UpDown : System.Windows.Forms.Form
    {
      private System.Windows.Forms.Button button2;
      private System.Windows.Forms.TextBox textBox1;
      private System.Windows.Forms.Button button1;
      private System.Windows.Forms.DomainUpDown UPDOWN_DOMAIN;
      private System.Windows.Forms.Label label1;
        /// 
        /// Required designer variable.
        /// 

        private System.ComponentModel.Container components = null;
        public UpDown()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();
            //
            // TODO: Add any constructor code after InitializeComponent call
            //
        }
        /// 
        /// Clean up any resources being used.
        /// 

        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null) 
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }
        #region Windows Form Designer generated code
        /// 
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// 

        private void InitializeComponent()
        {
         this.button2 = new System.Windows.Forms.Button();
         this.textBox1 = new System.Windows.Forms.TextBox();
         this.button1 = new System.Windows.Forms.Button();
         this.UPDOWN_DOMAIN = new System.Windows.Forms.DomainUpDown();
         this.label1 = new System.Windows.Forms.Label();
         this.SuspendLayout();
         // 
         // button2
         // 
         this.button2.Location = new System.Drawing.Point(136, 80);
         this.button2.Name = "button2";
         this.button2.TabIndex = 8;
         this.button2.Text = "Add Item";
         // 
         // textBox1
         // 
         this.textBox1.Location = new System.Drawing.Point(24, 80);
         this.textBox1.Name = "textBox1";
         this.textBox1.TabIndex = 7;
         this.textBox1.Text = "";
         // 
         // button1
         // 
         this.button1.Location = new System.Drawing.Point(264, 40);
         this.button1.Name = "button1";
         this.button1.Size = new System.Drawing.Size(64, 23);
         this.button1.TabIndex = 6;
         this.button1.Text = "Remove";
         // 
         // UPDOWN_DOMAIN
         // 
         this.UPDOWN_DOMAIN.BackColor = System.Drawing.Color.FromArgb(((System.Byte)(255)), ((System.Byte)(192)), ((System.Byte)(192)));
         this.UPDOWN_DOMAIN.Font = new System.Drawing.Font("Microsoft Sans Serif", 12F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
         this.UPDOWN_DOMAIN.ForeColor = System.Drawing.SystemColors.HotTrack;
         this.UPDOWN_DOMAIN.Location = new System.Drawing.Point(24, 40);
         this.UPDOWN_DOMAIN.Name = "UPDOWN_DOMAIN";
         this.UPDOWN_DOMAIN.Size = new System.Drawing.Size(232, 26);
         this.UPDOWN_DOMAIN.Sorted = true;
         this.UPDOWN_DOMAIN.TabIndex = 5;
         this.UPDOWN_DOMAIN.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
         this.UPDOWN_DOMAIN.UpDownAlign = System.Windows.Forms.LeftRightAlignment.Left;
         this.UPDOWN_DOMAIN.Wrap = true;
         // 
         // label1
         // 
         this.label1.Location = new System.Drawing.Point(24, 16);
         this.label1.Name = "label1";
         this.label1.Size = new System.Drawing.Size(136, 23);
         this.label1.TabIndex = 9;
         this.label1.Text = "UpDownDomain Control";
         // 
         // UpDown
         // 
         this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
         this.ClientSize = new System.Drawing.Size(344, 117);
         this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                                                      this.label1,
                                                                      this.UPDOWN_DOMAIN,
                                                                      this.button1,
                                                                      this.button2,
                                                                      this.textBox1});
         this.Name = "UpDown";
         this.Text = "UpDownDomain Control";
         this.Load += new System.EventHandler(this.UpDown_Load);
         this.ResumeLayout(false);
      }
        #endregion
        /// 
        /// The main entry point for the application.
        /// 

        [STAThread]
        static void Main() 
        {
            Application.Run(new UpDown());
        }
        private void UpDown_Load(object sender, System.EventArgs e)
        {
            // Populate the UpDown Domain control with string objects
            UPDOWN_DOMAIN.Items.Add("Visual C#");
            UPDOWN_DOMAIN.Items.Add("Visual C++");
            UPDOWN_DOMAIN.Items.Add("Visual VB");
            UPDOWN_DOMAIN.Items.Add("Managed C++");
            UPDOWN_DOMAIN.Items.Add("Crystal Reports");
            UPDOWN_DOMAIN.Items.Add("MFC");
            UPDOWN_DOMAIN.Items.Add("ATL");
            UPDOWN_DOMAIN.Items.Add("COM");
            UPDOWN_DOMAIN.Items.Add("DCOM");
            UPDOWN_DOMAIN.Items.Add("COM+");
            UPDOWN_DOMAIN.Items.Add("SETUP");
            UPDOWN_DOMAIN.Items.Add("COMMAND LINE");
            UPDOWN_DOMAIN.Items.Add("WINDOWS SERVICE");
            UPDOWN_DOMAIN.Items.Add("WINDOWS LIBRARY");
            UPDOWN_DOMAIN.Items.Add("ASP .NET WEB");
            UPDOWN_DOMAIN.Items.Add("DATABASE APPLICATION");
        }
        private void button1_Click(object sender, System.EventArgs e)
        {
            // Select the Item that want to remove
            int nItemSel = UPDOWN_DOMAIN.SelectedIndex;
            if ( nItemSel >= 0 ) 
            {
                // Remove the item at the location
                UPDOWN_DOMAIN.Items.RemoveAt(nItemSel);
                // Update the control
                UPDOWN_DOMAIN.Update();
                // Clear the edit box
                UPDOWN_DOMAIN.Text = "" ; 
            }
        }
        private void button2_Click(object sender, System.EventArgs e)
        {
            if ( textBox1.Text == "" ) 
            {
                MessageBox.Show("Enter a string to add");
                return ;
            }
            // Add the new string the UpDownDomain control
            UPDOWN_DOMAIN.Items.Add(textBox1.Text);
            textBox1.Text = "" ; 
        }
    }
}