Understanding Classic COM Interoperability With .NET Applications

using System;
using System.Runtime.InteropServices;
using System.Reflection;
using AIRLINEINFORMATIONLib;


public class CAirlineClient
{

	public static void Main()
	{

		///////////////////////////////////////////////
		/// EARLY BINDING EXAMPLE
		///////////////////////////////////////////////

		String strAirline = "Air Scooby IC 5678";
		String strFoodJunkieAirline = "Air Jughead TX 1234";
		try
	   	{
			AirlineInfo objAirlineInfo;
			
			// Create a new AirlineInfo Object
			objAirlineInfo = new AirlineInfo();	

			// Display the output after calling the GetAirileTiming method
			System.Console.WriteLine("Details for Airline {0} --> {1}",
				strAirline,objAirlineInfo.GetAirlineTiming(strAirline)); 

			// System.Console.WriteLine("Details for Airline {0} --> {1}",
			// strFoodJunkieAirline,objAirlineInfo.GetAirlineTiming(strFoodJunkieAirline)); 

	        }//try 
		catch(COMException e)
		{
			System.Console.WriteLine("Oops- We encountered an error for Airline {0}. The Error message is : {1}. The  Error code is {2}",
				strFoodJunkieAirline ,e.Message,e.ErrorCode);			  	

		}// catch 

		///////////////////////////////////////////////
		/// QUERY INTERFACE/ RT type Checking
		///////////////////////////////////////////////

	
		try	
		{
			AirlineInfo objAirlineInfo;
			IAirportFacilitiesInfo objFacilitiesInfo;
			
			// Create a new AirlineInfo object	
			objAirlineInfo = new AirlineInfo();
		
			// Invoke the GetAirlineTiming method	
			String strDetails = objAirlineInfo.GetAirlineTiming(strAirline);	

			// QI for the IAirportFacilitiesInfo interface		
			objFacilitiesInfo = (IAirportFacilitiesInfo)objAirlineInfo;
			
			//Invoke a method on the IAirportFacilitiesInfo interface
			System.Console.WriteLine("{0}",objFacilitiesInfo.GetInternetCafeLocations());

        	} //try
		catch(InvalidCastException eCast)
		{	
			System.Console.WriteLine("We got an InvalidCast Exception - Message is {0}",eCast.Message);   

		}//catch

		///////////////////////////////////////////////
		/// LATE BINDING
		///////////////////////////////////////////////


		try
		{

			object objAirlineLateBound;
			Type objTypeAirline;
		      	object[] arrayInputParams= { "Air Scooby IC 5678" };
			objTypeAirline = Type.GetTypeFromProgID
                               ("AirlineInformation.AirlineInfo");
			objAirlineLateBound = Activator.CreateInstance(objTypeAirline);
			String str = (String)objTypeAirline.InvokeMember("GetAirlineTiming",
									BindingFlags.Default |	
					                                BindingFlags.InvokeMethod,
					                                null,
									objAirlineLateBound,
									arrayInputParams);

			System.Console.WriteLine("{0}",str);

			String strTime = (String)objTypeAirline.InvokeMember("LocalTimeAtOrlando", 
								BindingFlags.Default | 										BindingFlags.GetProperty, 
								null, 
								objAirlineLateBound,
								new object [] {});


		      Console.WriteLine ("Hi there !. The Local Time at Orlando,Florida is: {0}", strTime);
        

		}//try late binding
		catch(COMException e)
		{
	
			System.Console.WriteLine("Oops- We encountered an error for Airline {0}. The Error message is : 					{1}. The Error code is {2}",strFoodJunkieAirline ,e.Message,e.ErrorCode);			  	

	       }//catch


	}// Main

}