using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Windows.Forms; class Form1 : Form { private int lightColor = 1; public Form1() { InitializeComponent(); } private void Form1_Paint(object sender, PaintEventArgs e) { Graphics g = e.Graphics; g.FillRectangle(Brushes.White, this.ClientRectangle); Rectangle r = new Rectangle(10, 10, 60, 180); g.FillRectangle(Brushes.LightGray, r); Rectangle r1 = new Rectangle(10, 10, 60, 60); Rectangle r2 = new Rectangle(10, 70, 60, 60); Rectangle r3 = new Rectangle(10, 130, 60, 60); switch (lightColor) { case 1: g.FillEllipse(Brushes.Red, r1); g.FillEllipse(Brushes.Black, r2); g.FillEllipse(Brushes.Black, r3); break; case 2: g.FillEllipse(Brushes.Black, r1); g.FillEllipse(Brushes.Yellow, r2); g.FillEllipse(Brushes.Black, r3); break; case 3: g.FillEllipse(Brushes.Black, r1); g.FillEllipse(Brushes.Black, r2); g.FillEllipse(Brushes.Green, r3); break; } } private void Form1_Click(object sender, EventArgs e) { lightColor++; if (lightColor == 4) lightColor = 1; this.Invalidate(); } private void InitializeComponent() { this.AutoScaleBaseSize = new System.Drawing.Size(5, 13); this.ClientSize = new System.Drawing.Size(292, 271); this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint); this.Click += new System.EventHandler(this.Form1_Click); } [STAThread] static void Main() { Application.EnableVisualStyles(); Application.Run(new Form1()); } }