using System;
using System.Windows.Forms;
using System.Diagnostics;
using System.ComponentModel;
using System.Runtime.InteropServices;

namespace GcDemo
{
  public partial class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();
      textBox1.Text = MyClassInstances.ToString();
      textBox2.Text = MyDispInstances.ToString();
    }

    MyClass myClass;
    private void button1_Click(object sender,EventArgs e)
    {
      for (int i = 0; i < 1000; i++)
        myClass = new MyClass();
      textBox1.Text = MyClassInstances.ToString();
      textBox2.Text = MyClassInstances.ToString();
    }
    public static int MyClassInstances = 0;
    public static int MyDispInstances = 0;
  }

  class MyClass
  {
    public MyDisposable myclass = new MyDisposable();
  
    public MyClass() { Form1.MyClassInstances++; }
    ~MyClass()       { Form1.MyClassInstances--; }
  }

  public class MyDisposable : IDisposable
  {
    [DllImport("coredll.dll")]
    static extern bool CloseHandle(IntPtr hObject);

    private IntPtr handle;
    private Component Components = null;
    private bool disposed = false;

    public MyDisposable()
    {
      Form1.MyDispInstances++;
    }

    public void Dispose()
    {
      Dispose(true);
      GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposing)
    {
      if (!this.disposed)
      {
        if (disposing)
        {
          Components.Dispose();
        }
        if (handle != IntPtr.Zero) CloseHandle(handle); 
        handle = IntPtr.Zero;
      }
      disposed = true;
    }

    ~MyDisposable()
    {
      Dispose(false);
      Form1.MyDispInstances++;
    }

    public void DoSomething()
    {
      if (this.disposed)
      {
        throw new ObjectDisposedException("MeinObjekt");
      }
    }
  }
}