事件

using System;
using System.ComponentModel;
using System.Windows.Forms;
using System.Resources;
using System.Drawing;

public class MyForm : Form {
   private Button red;
   private Button blue;
   private Button green;

   public MyForm() : base() {  
      InitializeComponent();  
   }

   protected override void Dispose(bool disposing) {
      base.Dispose(disposing);
   }
  
// InitializeComponent is a helper method for the constructor.
// It is included for consistency with code that is
// auto-generated by the Windows Forms designer in Visual Studio.
   private void InitializeComponent() {
  
// A delegate for the click event of a button. The argument to
// the constructor contains a reference to the method that performs the
// event handling logic.
      EventHandler handler = new EventHandler(button_Click);
  
// Creates three buttons, sets their properties, and attaches
// an event handler to each button.

      red = new Button();
      red.Text = "Red";
      red.Location = new Point(100, 50);
      red.Size = new Size(50, 50);
      red.Click +=handler;
      Controls.Add(red);
     
      blue = new Button();
      blue.Text = "Blue";
      blue.Location = new Point(100, 100);
      blue.Size = new Size(50, 50);
      blue.Click += handler;
      Controls.Add(blue);
     
      green = new Button();
      green.Text = "Green";
      green.Location = new Point(100, 150);
      green.Size = new Size(50, 50);
      green.Click += handler;
      Controls.Add(green);     
      }
     
   // Event handler.
   private void button_Click(object sender, EventArgs e) {
            if (sender == red) this.BackColor = Color.Red ;
                  else if (sender == blue) this.BackColor = Color.Blue;
                  else this.BackColor = Color.Green;
        }
   // The STAThreadAttribute informs the common language runtime that
   // Windows Forms uses the single-threaded apartment model.
  [STAThread]
   public static void Main(string[] args) {
   Application.Run(new MyForm());
   }
  
}