using System;
using System.Drawing;
using System.Windows.Forms;
using System.Collections.Generic;

public class Form1 : Form {
	Panel panel1;
	Panel panel2;
	Panel panel3;
	Button button1,
		button2,
		button3;
	Dictionary<Button, Panel> _dic = new Dictionary<Button, Panel>();
	public Form1() {
		this.ClientSize = new Size(500, 500);
		this.Text = "panel";
		panel1 = new Panel();
		panel1.Location = new Point(10, 50);
		panel1.Width = 400;
		panel1.Height = 400;
		panel1.BackColor = Color.Gray;
		panel2 = new Panel();
		panel2.Location = new Point(10, 50);
		panel2.Width = 400;
		panel2.Height = 400;
		panel2.BackColor = Color.Red;
		panel3 = new Panel();
		panel3.Location = new Point(10, 50);
		panel3.Width = 400;
		panel3.Height = 400;
		panel3.BackColor = Color.Blue;
		button1 = new Button();
		button1.Location = new Point(10, 10);
		button1.Size = new Size(100, 30);
		button1.Text = "1";
		button2 = new Button();
		button2.Location = new Point(160, 10);
		button2.Size = new Size(100, 30);
		button2.Text = "2";
		button3 = new Button();
		button3.Location = new Point(310, 10);
		button3.Size = new Size(100, 30);
		button3.Text = "3";
		this.Controls.Add(panel1);
		this.Controls.Add(panel2);
		this.Controls.Add(panel3);
		this.Controls.Add(button1);
		this.Controls.Add(button2);
		this.Controls.Add(button3);
		_dic.Add(this.button1, this.panel1);
		_dic.Add(this.button2, this.panel2);
		_dic.Add(this.button3, this.panel3);
		AddEvent();
		SelectPanel(this.button3);
	}
	private void AddEvent() {
		foreach (KeyValuePair<Button, Panel> pair in _dic)
		{
			Button button = pair.Key;
			button.Click += new System.EventHandler(this.Button_Click);
		}
	}
	private void Button_Click(object sender, EventArgs e) {
		Button button = (Button) sender;
		SelectPanel(button);
	}
	private void SelectPanel(Button selectedButton) {
		foreach (KeyValuePair<Button, Panel> pair in _dic)
		{
			Button button = pair.Key;
			Panel panel = pair.Value;
			if (button.Equals(selectedButton))
			{
				button.BackColor = Color.DarkBlue;
				button.ForeColor = Color.White;
				panel.Visible = true;
			}
			else
			{
				button.BackColor = Color.Gray;
				button.ForeColor = Color.Black;
				panel.Visible = false;
			}
		}
	}
	[STAThread]
	public static void Main() {
		Application.Run(new Form1());
	}
}