Using the Remoting Callbacks in .Net Applications.

//--------------------------------------------
// Written by Roman Kiss (rkiss@pathcom.com)
// November 14, 2001
// 
// history:
// RK	10142001	init
//--------------------------------------------

using System;
using System.Diagnostics;
using System.Threading;
using System.Drawing;
using System.Collections;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Configuration;
//
using System.Runtime.Remoting;
using System.Runtime.Remoting.Activation;
using System.Runtime.Remoting.Lifetime;
using System.Runtime.Remoting.Messaging;
using System.Runtime.Remoting.Channels.Tcp;
using System.Runtime.Remoting.Channels.Http;
using System.Reflection;
using System.Runtime.InteropServices;
//
using RKiss.RemoteObject;			// abstract definitions
using RKiss.RemoteCallbackLib;		// custom attribute, subscriber



namespace RKiss.RemoteWindowsForm
{
	// delegate for asynch invoking
	public delegate string DelegateGiveMeCallback(int timeinsec, string ticketId, object objwire);

	// -----------< Callback class >-------------------------------------------
	public class CallbackClass : MarshalByRefObject
	{	
		private Form1 _parent = null;
		private bool  _state = false;
		public Form1 Parent	{ set { _parent = value; }}
		public bool State   { set { lock(this) { _state = value; }}}
		// set a leaseing time for infinity
		public override Object InitializeLifetimeService()
		{
			ILease lease = (ILease)base.InitializeLifetimeService();
			if(lease.CurrentState == LeaseState.Initial)  
			{
				lease.InitialLeaseTime = TimeSpan.FromMinutes(0);
			}
			return lease;
		}
		//
		// CallbackMethod
		public bool Progress(string sender, object e) 
		{
			// fire&forget
			ThreadPool.QueueUserWorkItem(new WaitCallback(DispatchEvent), e);
			return _state;
		}
		// helper
		private void DispatchEvent(object e) 
		{
			CallbackEventArgs cea = e as CallbackEventArgs;
			// a simple work with the parent's control
			lock(this) 
			{
				if(cea.TicketId == "ProgressBar") 
				{
					if(cea.State is int)
					{
						_parent.TextBoxStatus.Text = cea.State.ToString();
						_parent.ProgressBarStatus.PerformStep();
					}
					else
					if(cea.State is string)
						_parent.TextBoxStatus.Text = cea.State.ToString();
				}
				else
				if(cea.TicketId == "TextBox") 
				{
					if(_parent.TextBoxStatus.BackColor == Color.Yellow)
						_parent.TextBoxStatus.BackColor = Color.White;
					else
						_parent.TextBoxStatus.BackColor = Color.Yellow;
				}
				else
				if(cea.TicketId == "Button") 
				{
					if(_parent.ButtonRM.ForeColor == Color.Magenta)
						_parent.ButtonRM.ForeColor = Color.Black;
					else
						_parent.ButtonRM.ForeColor = Color.Magenta;
				}
			}
		}
	} // end of the CallbackClass
	


	// Windows Form
	public class Form1 : System.Windows.Forms.Form
	{
		private System.Windows.Forms.Button buttonRM;
		private System.Windows.Forms.TextBox textBoxStatus;
		private System.Windows.Forms.ProgressBar progressBarStatus;

		// --------< remoting and callback >------------------------------------
		[RemoteCallback("tcp", desc="Callbacks Test")]
		public CallbackClass cb = null;
		// Remote ObjectA
		private IRmObject roA = null;
		// Remote ObjectX
		private IRmObject roX = null;
		// Remote ObjectWS
		private IRmObject roWS = null;
		// callback Admin
		private RemoteCallbackSubscriber sub = null;
		// Access to the controls
		public ProgressBar ProgressBarStatus { get { return progressBarStatus; }}
		public TextBox     TextBoxStatus { get { return textBoxStatus; }}
		public Button      ButtonRM { get { return buttonRM; }}
	
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;
		
		public Form1()
		{
			InitializeComponent();

			try 
			{
				sub = new RemoteCallbackSubscriber(this);
				cb.Parent = this;	// we need an access to the parent properties

				// get the remoting uriAddress
				NameValueCollection uriAddr = (NameValueCollection)ConfigurationSettings.GetConfig("Client/urlAddress");
				string uriObjectA = (string)uriAddr["objectA"];
				string uriObjectX = (string)uriAddr["objectX"];
				string uriObjectWS = (string)uriAddr["objectWS"];

				// type of the Remote Interface
				Type typeofRI = typeof(RKiss.RemoteObject.IRmObject);

				// create a proxy of the remote objects
				roA = (IRmObject)Activator.GetObject(typeofRI, uriObjectA);
				roX = (IRmObject)Activator.GetObject(typeofRI, uriObjectX);
				roWS = (IRmObject)Activator.GetObject(typeofRI, uriObjectWS); 
				//
				// (sub["cb"] as TcpChannel).StartListening(0);	// sample how to control a Tcp channel

				// echo test
				textBoxStatus.Text = roWS.Echo(roA.Echo(roX.Echo("This is an ECHO Message")));
			}
			catch(Exception ex)
			{
				textBoxStatus.Text = ex.Message;
				buttonRM.Hide();
			}
		}

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.textBoxStatus = new System.Windows.Forms.TextBox();
			this.buttonRM = new System.Windows.Forms.Button();
			this.progressBarStatus = new System.Windows.Forms.ProgressBar();
			this.SuspendLayout();
			// 
			// textBoxStatus
			// 
			this.textBoxStatus.Anchor = ((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
				| System.Windows.Forms.AnchorStyles.Right);
			this.textBoxStatus.BackColor = System.Drawing.Color.White;
			this.textBoxStatus.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
			this.textBoxStatus.Location = new System.Drawing.Point(8, 32);
			this.textBoxStatus.Name = "textBoxStatus";
			this.textBoxStatus.ReadOnly = true;
			this.textBoxStatus.Size = new System.Drawing.Size(224, 20);
			this.textBoxStatus.TabIndex = 2;
			this.textBoxStatus.Text = "status";
			// 
			// buttonRM
			// 
			this.buttonRM.Anchor = (System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right);
			this.buttonRM.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
			this.buttonRM.ForeColor = System.Drawing.SystemColors.ControlText;
			this.buttonRM.Location = new System.Drawing.Point(232, 32);
			this.buttonRM.Name = "buttonRM";
			this.buttonRM.Size = new System.Drawing.Size(64, 23);
			this.buttonRM.TabIndex = 1;
			this.buttonRM.Text = "Run";
			this.buttonRM.Click += new System.EventHandler(this.buttonRM_Click);
			// 
			// progressBarStatus
			// 
			this.progressBarStatus.Anchor = ((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
				| System.Windows.Forms.AnchorStyles.Right);
			this.progressBarStatus.Location = new System.Drawing.Point(8, 8);
			this.progressBarStatus.Name = "progressBarStatus";
			this.progressBarStatus.Size = new System.Drawing.Size(288, 16);
			this.progressBarStatus.TabIndex = 0;
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(304, 61);
			this.Controls.AddRange(new System.Windows.Forms.Control[] {
																		  this.textBoxStatus,
																		  this.buttonRM,
																		  this.progressBarStatus});
			this.Name = "Form1";
			this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
			this.Text = "Remote Callback";
			this.TopMost = true;
			this.ResumeLayout(false);

		}
		#endregion

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}
		// run in the objectA, objectX and objectWS simultaneusly
		private void buttonRM_Click(object sender, System.EventArgs e)
		{
			try 
			{
				if(buttonRM.Text == "Run") 
				{
					// client state
					buttonRM.Text = "Busy";
					progressBarStatus.Value = 0;
					textBoxStatus.Text = string.Empty;
					cb.State = true;
					//
					// arguments
					int timeinsec = 10;
					string ticketId = "ProgressBar";
					RemoteCallback wire = new RemoteCallback(cb.Progress);
					//
					// invoking method on the objectA
					AsyncCallback acbA = new AsyncCallback(asyncCallBackA);
					DelegateGiveMeCallback dA = new DelegateGiveMeCallback(roA.GiveMeCallback);
					IAsyncResult arA = dA.BeginInvoke(timeinsec, ticketId, wire, acbA, null);
					//
					// invoking method on the objectX
					AsyncCallback acbX = new AsyncCallback(asyncCallBackX);
					DelegateGiveMeCallback dX = new DelegateGiveMeCallback(roX.GiveMeCallback);
					IAsyncResult arX = dX.BeginInvoke(timeinsec, "TextBox", wire, acbX, null);
					//
					// invoking method on the objectWS
					AsyncCallback acbWS = new AsyncCallback(asyncCallBackWS);
					DelegateGiveMeCallback dWS = new DelegateGiveMeCallback(roWS.GiveMeCallback);
					IAsyncResult arWS = dWS.BeginInvoke(timeinsec, "Button", wire, acbWS, null);
					//
					buttonRM.Text = "Abort";
				}
				else
				if(buttonRM.Text == "Abort")
				{
					cb.State = false;
				}
			}
			catch(Exception ex)
			{
				textBoxStatus.Text = ex.Message;
				buttonRM.Text = "Run";
			}
		}
		// async result from the remoting objects
		private void asyncCallBackA(IAsyncResult ar)
		{
			DelegateGiveMeCallback d = (DelegateGiveMeCallback)((AsyncResult)ar).AsyncDelegate;
			object o = d.EndInvoke(ar);
			buttonRM.Text = "Run";
		}
		private void asyncCallBackX(IAsyncResult ar)
		{
			DelegateGiveMeCallback d = (DelegateGiveMeCallback)((AsyncResult)ar).AsyncDelegate;
			object o = d.EndInvoke(ar);
			buttonRM.Text = "Run";
		}
		private void asyncCallBackWS(IAsyncResult ar)
		{
			DelegateGiveMeCallback d = (DelegateGiveMeCallback)((AsyncResult)ar).AsyncDelegate;
			object o = d.EndInvoke(ar);
			buttonRM.Text = "Run";
		}
	}
}