Using events for thread synchronization

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Threading;

namespace ThreadSync01
{
    // For .NET 2.0 support
    public delegate void Action();

	/// <summary>
	/// Summary description for Form1.
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		private System.Windows.Forms.ListBox listBox1;
		private System.Windows.Forms.Button button1;
		private System.Windows.Forms.Button button2;
		private System.Windows.Forms.Button button3;
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;

		public Form1()
		{
			//
			// Required for Windows Form Designer support
			//
			InitializeComponent();

			m_mre = new ManualResetEvent(false);
			m_mreB = new ManualResetEvent(false);
			m_mre_array = new ManualResetEvent[2];
			m_mre_array[0]=m_mre;
			m_mre_array[1]=m_mreB;

			//
			// TODO: Add any constructor code after InitializeComponent call
			//
		}

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			try
			{
				base.Dispose( disposing );
			}
			catch
			{
				//I had to do this cause this kept raising exceptions.
				//The reason was that the threads were still active.
				//The solution in a real life situation would be use 
				//an event here to wait till all threads are finished.
				//Ironic that an example program for a thread sync
				//mechanism does not use any thread sync --- Nish
			}
		}

		#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.listBox1 = new System.Windows.Forms.ListBox();
			this.button1 = new System.Windows.Forms.Button();
			this.button2 = new System.Windows.Forms.Button();
			this.button3 = new System.Windows.Forms.Button();
			this.SuspendLayout();
			// 
			// listBox1
			// 
			this.listBox1.Location = new System.Drawing.Point(16, 16);
			this.listBox1.Name = "listBox1";
			this.listBox1.Size = new System.Drawing.Size(272, 212);
			this.listBox1.TabIndex = 0;
			// 
			// button1
			// 
			this.button1.Location = new System.Drawing.Point(16, 248);
			this.button1.Name = "button1";
			this.button1.Size = new System.Drawing.Size(72, 24);
			this.button1.TabIndex = 1;
			this.button1.Text = "Try1";
			this.button1.Click += new System.EventHandler(this.button1_Click);
			// 
			// button2
			// 
			this.button2.Location = new System.Drawing.Point(112, 248);
			this.button2.Name = "button2";
			this.button2.Size = new System.Drawing.Size(72, 24);
			this.button2.TabIndex = 2;
			this.button2.Text = "Try2";
			this.button2.Click += new System.EventHandler(this.button2_Click);
			// 
			// button3
			// 
			this.button3.Location = new System.Drawing.Point(216, 248);
			this.button3.Name = "button3";
			this.button3.Size = new System.Drawing.Size(72, 24);
			this.button3.TabIndex = 3;
			this.button3.Text = "Try3";
			this.button3.Click += new System.EventHandler(this.button3_Click);
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(306, 288);
			this.Controls.AddRange(new System.Windows.Forms.Control[] {
																		  this.button3,
																		  this.button2,
																		  this.button1,
																		  this.listBox1});
			this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
			this.Name = "Form1";
			this.Text = "ThreadSync01";
			this.ResumeLayout(false);

		}
		#endregion

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[MTAThread]
		static void Main() 
		{
			try
			{
				Application.Run(new Form1());
			}
			catch
			{
				//same explanation as in Dispose(...) - Nish
			}
		}

		public int m_x=0;

		public void ReadThread10()
		{
			int a = 10;
			for(int y=0;y<5;y++)
			{
				string s = "ReadThread10";
				s = s + " # multiplier= ";
				s = s + Convert.ToString(a) + " # ";
				s = s + a * m_x;
                listBox1.BeginInvoke((Action)(() => listBox1.Items.Add(s)));
				Thread.Sleep(1000);
			}
		}

		public void ReadThread20()
		{
			int a = 20;
			for(int y=0;y<5;y++)
			{
				string s = "ReadThread20";
				s = s + " # multiplier= ";
				s = s + Convert.ToString(a) + " # ";
				s = s + a * m_x;
                listBox1.BeginInvoke((Action)(() => listBox1.Items.Add(s)));
				Thread.Sleep(1000);
			}
		}

		public void WriteThread()
		{
			Thread.Sleep(1000);
			m_x=3;
		}		

		public void SafeWriteThread()
		{
			m_mre.Reset();
			WriteThread();
			m_mre.Set();
		}

		public void SafeWriteThreadB()
		{	
			m_mreB.Reset();
			m_mre.WaitOne();
			Thread.Sleep(1000);
			m_x+=3;			
			m_mreB.Set();
		}

		public void SafeReadThread10()
		{
			m_mre.WaitOne();
			ReadThread10();
		}

		public void SafeReadThread20()
		{
			m_mre.WaitOne();
			ReadThread20();
		}

		public void SafeReadThread10B()
		{
			WaitHandle.WaitAll(m_mre_array);
			ReadThread10();
		}

		public void SafeReadThread20B()
		{
			WaitHandle.WaitAll(m_mre_array);
			ReadThread20();
		}

		private void button1_Click(object sender, System.EventArgs e)
		{
			listBox1.Items.Clear();
			listBox1.Items.Add("No sync mechanism used");
			listBox1.Items.Add("");
			Thread t0 = new Thread(new ThreadStart(WriteThread));
			Thread t1 = new Thread(new ThreadStart(ReadThread10));
			Thread t2 = new Thread(new ThreadStart(ReadThread20));
			t0.IsBackground=true;
			t1.IsBackground=true;
			t2.IsBackground=true;
			t0.Start();
			t1.Start();
			t2.Start();
		}

		private void button2_Click(object sender, System.EventArgs e)
		{
			listBox1.Items.Clear();
			listBox1.Items.Add("One Write thread - Multiple Read threads");
			listBox1.Items.Add("");
			Thread t0 = new Thread(new ThreadStart(SafeWriteThread));
			Thread t1 = new Thread(new ThreadStart(SafeReadThread10));
			Thread t2 = new Thread(new ThreadStart(SafeReadThread20));
			t0.IsBackground=true;
			t1.IsBackground=true;
			t2.IsBackground=true;
			t0.Start();
			t1.Start();
			t2.Start();
		}

		public ManualResetEvent m_mre;
		public ManualResetEvent m_mreB;
		public ManualResetEvent[] m_mre_array;

		private void button3_Click(object sender, System.EventArgs e)
		{
			listBox1.Items.Clear();
			listBox1.Items.Add("Multiple Write threads - Multiple Read threads");
			listBox1.Items.Add("");
			Thread t0 = new Thread(new ThreadStart(SafeWriteThread));
			Thread t0B = new Thread(new ThreadStart(SafeWriteThreadB));
			Thread t1 = new Thread(new ThreadStart(SafeReadThread10B));
			Thread t2 = new Thread(new ThreadStart(SafeReadThread20B));
			t0.IsBackground=true;
			t0B.IsBackground=true;
			t1.IsBackground=true;
			t2.IsBackground=true;
			t0.Start();
			t0B.Start();
			t1.Start();
			t2.Start();
		}
	}
}