Understanding Classic COM Interoperability With .NET Applications

namespace AirlineNotifyClient
{
    using System;
    using System.Drawing;
    using System.ComponentModel;
    using System.Windows.Forms;
    using System.Text;
    using AirlineNotifyMetadata;

    public class AirlineNotifyForm : System.Windows.Forms.Form
    {
        private Container components;
        private System.Windows.Forms.CheckBox checkBoxPaging;
        private System.Windows.Forms.ListBox listPager;
        private AirlineArrivalPager m_pager = null;

        public AirlineNotifyForm()
        {
            InitializeComponent();

            // Subscribe to event notifications from
            // the AirlineArrivalPager component
            subscribePaging();
        }

        public override void Dispose()
        {
            base.Dispose();
            components.Dispose();
        }

        private void InitializeComponent()
        {
	this.components = new System.ComponentModel.Container ();
	this.listPager = new ListBox ();
	this.checkBoxPaging = new CheckBox ();
	listPager.Location = new System.Drawing.Point (0, 8);
	listPager.Size = new System.Drawing.Size (280, 102);
	listPager.ForeColor = System.Drawing.Color.Chartreuse;
	listPager.Font = new System.Drawing.Font ("Arial", 8, System.Drawing.FontStyle.Bold);
	listPager.TabIndex = 0;
	listPager.BackColor = System.Drawing.Color.Black;
	checkBoxPaging.Checked = true;
	checkBoxPaging.Location = new System.Drawing.Point (8, 120);
	checkBoxPaging.Text = "Enable Paging";
	checkBoxPaging.Size = new System.Drawing.Size (224, 16);
	checkBoxPaging.CheckState = System.Windows.Forms.CheckState.Checked;
	checkBoxPaging.TabIndex = 1;
	checkBoxPaging.CheckedChanged += new System.EventHandler (this.checkBoxPaging_CheckedChanged);
	this.Text = "My Airline Pager";
	this.AutoScaleBaseSize = new System.Drawing.Size (5, 13);
	this.ClientSize = new System.Drawing.Size (288, 149);
	this.Controls.Add (this.checkBoxPaging);
	this.Controls.Add (this.listPager);

       }/* end InitializeComponent */
		
        /// <summary>
        ///    This is the handler function that will be called when the
        ///    checkbox is checked(to enable Airline arrival paging) or unchecked 
        ///    (to disable Airline arrival paging)
        /// </summary>
        protected void checkBoxPaging_CheckedChanged (object sender, System.EventArgs e)
        {
	if(checkBoxPaging.Checked)
	{
	     // If checked, register the delegate referencing the OnMyPagerNotify
	     // to the OnAirlineArrivedEvent list (ICP::Advise)
	     m_pager.OnAirlineArrivedEvent +=
                                 new _IAirlineArrivalPagerEvents_OnAirlineArrivedEventEventHandler(OnMyPagerNotify);

	}/* end if */
             	else
	{
	     // If Unchecked, remove the delegate referencing the OnMyPagerNotify
	     // from the OnAirlineArrivedEvent list (ICP::UnAdvise)
	     m_pager.OnAirlineArrivedEvent -=
		new _IAirlineArrivalPagerEvents_OnAirlineArrivedEventEventHandler(OnMyPagerNotify);
	
	}/* end else */

         }
		
         /// <summary>
         ///    Creates an AirlineArrivalPager object and subscribes to
         ///    the OnAirlineArrivedEvent event notification.
         /// </summary>
         void subscribePaging() {

              // Create an AirlineArrivalPager object
	m_pager = new AirlineArrivalPager();

	// Add the delegate referencing the OnMyPagerNotify method
	// to the OnAirlineArrivedEvent event list (ICP::Advise)
	m_pager.OnAirlineArrivedEvent +=
		new _IAirlineArrivalPagerEvents_OnAirlineArrivedEventEventHandler(OnMyPagerNotify);

         }/* end subscribePaging */
		

         /// <summary>
         ///    This is the handler function that is referenced by the
         ///    delegate to receive OnAirlineArrivedEvent notifications
         /// </summary>
         /// <param name="strAirline">Indicates the name of the airline that just arrived.</param>
         /// <param name="strTerminal">Indicates the Terminal/Gate where it has arrived.</param>
         public int OnMyPagerNotify(String strAirline, String strTerminal) 
         {
	StringBuilder strDetails = new StringBuilder("Airline ");
	strDetails.Append(strAirline);
	strDetails.Append(" has arrived in ");
	strDetails.Append(strTerminal);
	listPager.Items.Insert(0,strDetails);
	return 0;

        }/* end OnMyPagerNotify */

		
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        public static void Main(string[] args) 
        {
            Application.Run(new AirlineNotifyForm());

        }/* end Main */

    }/* end class */

}/* end Namespace */