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

namespace WindowsApplication6
{
   public partial class Form2 : Form
   {
       public Form2()
       {
           InitializeComponent();
       }

       public unsafe System.Windows.Forms.Form* F1;

       private void button1_Click(object sender, EventArgs e)
       {
           textBox1.Text = "OK!";
       }

    }
}

public unsafe System.Windows.Forms.Form* F1