Form hide

   

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

  public class Form2 : Form
  {
    private System.Windows.Forms.Button Button3;
    private System.Windows.Forms.Button Button2;
    private System.Windows.Forms.Button Button1;
      
      
    public Form2()
    {
      InitializeComponent();
    }
    private void InitializeComponent()
    {
      this.Button3 = new System.Windows.Forms.Button();
      this.Button2 = new System.Windows.Forms.Button();
      this.Button1 = new System.Windows.Forms.Button();
      this.SuspendLayout();
      // 
      // Button3
      // 
      this.Button3.Location = new System.Drawing.Point(120, 56);
      this.Button3.Name = "Button3";
      this.Button3.Size = new System.Drawing.Size(88, 32);
      this.Button3.TabIndex = 8;
      this.Button3.Text = "Become Child of Parent2";
      this.Button3.Click += new System.EventHandler(this.Button3_Click);
      // 
      // Button2
      // 
      this.Button2.Location = new System.Drawing.Point(12, 56);
      this.Button2.Name = "Button2";
      this.Button2.Size = new System.Drawing.Size(88, 32);
      this.Button2.TabIndex = 7;
      this.Button2.Text = "Become Child of Parent1";
      this.Button2.Click += new System.EventHandler(this.Button2_Click);
      // 
      // Button1
      // 
      this.Button1.Location = new System.Drawing.Point(12, 12);
      this.Button1.Name = "Button1";
      this.Button1.Size = new System.Drawing.Size(88, 32);
      this.Button1.TabIndex = 6;
      this.Button1.Text = "Become Parent";
      this.Button1.Click += new System.EventHandler(this.Button1_Click);
      // 
      // Form2
      // 
      this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
      this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
      this.ClientSize = new System.Drawing.Size(292, 154);
      this.Controls.Add(this.Button3);
      this.Controls.Add(this.Button2);
      this.Controls.Add(this.Button1);
      this.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
      this.Name = "Form2";
      this.Text = "Form2";
      this.ResumeLayout(false);

    }

    private void Button1_Click(object sender, System.EventArgs e)
    {
      this.Hide();
      this.MdiParent = null;
      this.IsMdiContainer = true;
      this.Show();
    }

    private void Button2_Click(object sender, System.EventArgs e)
    {
      this.Hide();
      this.IsMdiContainer = false;
      this.MdiParent = Program.Main2;
      this.Show();
    }

    private void Button3_Click(object sender, System.EventArgs e)
    {
      this.Hide();
      this.IsMdiContainer = false;
      this.MdiParent = Program.Main1;
      this.Show();
    }
  }

  public class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();
    }

    private void Form1_FormClosed(object sender, FormClosedEventArgs e)
    {
      Application.Exit();
    }
    private void InitializeComponent()
    {
      this.SuspendLayout();
      this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
      this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
      this.ClientSize = new System.Drawing.Size(422, 351);
      this.IsMdiContainer = true;
      this.Name = "Form1";
      this.Text = "Form1";
      this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.Form1_FormClosed);
      this.ResumeLayout(false);

    }
  }

  static class Program
  {
    public static Form1 Main1 = new Form1();
    public static Form1 Main2 = new Form1();
    public static Form2 Child = new Form2();

    [STAThread]
    public static void Main()
    {
      Application.EnableVisualStyles();
      Main1.Text = "Parent 2";
      Main2.Text = "Parent 1";
      Main1.Show();
      Main2.Show();

      Child.MdiParent = Main2;
      Child.Show();

      System.Windows.Forms.Application.Run();
    }
  }