Windows Forms

Private Sub nudtags_ValueChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles nudtags.ValueChanged
    If Not DesignMode Then
        DoMethod(nudtags.Value)
    End If
End Sub

//Purpose:to find prime numbers

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Collections;
using System.Threading;
using System.IO;

namespace Primes
{
	
	public class MainForm : System.Windows.Forms.Form
	{
		private System.Windows.Forms.Button cmdDoit;
		private System.Windows.Forms.ListBox lbPrimes;
		private System.Windows.Forms.ProgressBar pbPrimes;
		private System.Windows.Forms.Label lblValue;
		Thread t;
		public MainForm()
		{
			
			InitializeComponent();
			
			
		}
		
		[STAThread]
		public static void Main(string[] args)
		{
			Application.Run(new MainForm());
		}
		
		#region Windows Forms Designer generated code
		/// <summary>
		/// This method is required for Windows Forms designer support.
		/// Do not change the method contents inside the source code editor. The Forms designer might
		/// not be able to load this method if it was changed manually.
		/// </summary>
		private void InitializeComponent() {
			this.lblValue = new System.Windows.Forms.Label();
			this.pbPrimes = new System.Windows.Forms.ProgressBar();
			this.lbPrimes = new System.Windows.Forms.ListBox();
			this.cmdDoit = new System.Windows.Forms.Button();
			this.SuspendLayout();
			// 
			// lblValue
			// 
			this.lblValue.Location = new System.Drawing.Point(8, 64);
			this.lblValue.Name = "lblValue";
			this.lblValue.TabIndex = 3;
			// 
			// pbPrimes
			// 
			this.pbPrimes.Location = new System.Drawing.Point(8, 40);
			this.pbPrimes.Name = "pbPrimes";
			this.pbPrimes.TabIndex = 2;
			// 
			// lbPrimes
			// 
			this.lbPrimes.Location = new System.Drawing.Point(8, 96);
			this.lbPrimes.Name = "lbPrimes";
			this.lbPrimes.Size = new System.Drawing.Size(136, 290);
			this.lbPrimes.TabIndex = 0;
			// 
			// cmdDoit
			// 
			this.cmdDoit.Location = new System.Drawing.Point(8, 8);
			this.cmdDoit.Name = "cmdDoit";
			this.cmdDoit.TabIndex = 1;
			this.cmdDoit.Text = "Calculate";
			this.cmdDoit.Click += new System.EventHandler(this.CmdDoitClick);
			// 
			// MainForm
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(152, 398);
			this.Controls.Add(this.lblValue);
			this.Controls.Add(this.pbPrimes);
			this.Controls.Add(this.cmdDoit);
			this.Controls.Add(this.lbPrimes);
			this.Name = "MainForm";
			this.Text = "Primes";
			this.Closing += new System.ComponentModel.CancelEventHandler(this.MainFormClosing);
			this.Load += new System.EventHandler(this.MainFormLoad);
			this.ResumeLayout(false);
		}
		#endregion
		void MainFormLoad(object sender, System.EventArgs e)
		{
			
		}
		
		void CmdDoitClick(object sender, System.EventArgs e)
		{
            Control.CheckForIllegalCrossThreadCalls = false; //so that I can access controls from the thread(Not necessary in .net 1.1)
			t = new Thread(new ThreadStart(Calc));
			t.Start();
            //you can use t.Suspend() and t.Resume() to pause and continue
		}
		
		void Calc() {
			int count = 0;
			int max = 1000000; //will find primes up to this number
            this.pbPrimes.Maximum = max;
            this.pbPrimes.Value = 0;

			ArrayList al = new ArrayList();
			for (int x = 1; x <= max; x++) {
				bool prime = true;
				for (int y = 2; y < (x/2)+1; y++) { //to check if a number is prime
					if ((x % y) == 0) { //will find any other multiples of x
						prime = false;
					}
				}
				if (prime) {
					al.Add(x);
					count++;
				}
                pbPrimes.Value++;
				lblValue.Text = pbPrimes.Value.ToString();
                
                
			}
            
			lbPrimes.DataSource = al;
            
            //writing to file
			FileStream fs = new FileStream("Primes.txt",FileMode.Create);
			BufferedStream bs = new BufferedStream(fs);
			StreamWriter sw = new StreamWriter(bs);
			foreach (int num in al) {
				sw.WriteLine(num.ToString());
			}
			sw.Close();
			bs.Close();
			fs.Close();

			MessageBox.Show(count.ToString() + " Primes were found and written to Primes.txt");
		}
		
		void MainFormClosing(object sender, System.ComponentModel.CancelEventArgs e)
		{
			try {
				t.Abort();
			} catch (Exception ex) {
				MessageBox.Show(ex.ToString() + "  Thread could not be stopped");
			}
		}
		
	}
}