using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;



namespace WindowsFormsApplication1

{

    public partial class Form1 : Form

    {

        private Form2 mForm2;



        public Form1()

        {

            InitializeComponent();

        }



        private void button1_Click(object sender, EventArgs e)

        {

            if (mForm2 == null)

            {

                mForm2 = new Form2();

                mForm2.Show();

                mForm2.FormClosed += new FormClosedEventHandler(mForm2_FormClosed);

            }

        }



        void mForm2_FormClosed(object sender, FormClosedEventArgs e)

        {

            mForm2 = null;

        }



        private void DockForm(Form f)

        {

            if (tabPage1.Controls.Contains(f)) return;

            f.TopLevel = false;

            f.FormBorderStyle = FormBorderStyle.None;

            tabPage1.Controls.Add(f);

            f.Dock = DockStyle.Fill;

        }



        private void button2_Click(object sender, EventArgs e)

        {

            if (mForm2 != null) DockForm(mForm2);

        }

    }

}