// created on 20.10.2001 at 18:04
//This example has 2 classes
//1. MyFilter, which exposes the IMesageFilter interface
//The PreFilterMessage method is overriden for our needs
//2. MainForm, which is our main form
using System;
using System.Windows.Forms;
class MyFilter:IMessageFilter //gets the left mouse button messages
{
public bool PreFilterMessage(ref Message m)
{
if (m.Msg>=513 && m.Msg<=515)
{
Console.WriteLine("mouse left button event NOT accepted!Filter working...");
return(true);
}
return(false);
}
}
class MainForm : Form
{
private Button btn=new Button();
public MainForm() //MainForm's constructor
{
//let's put a button on the form
  btn.Left=30;
btn.Top=30;
btn.Width=150;
btn.Text="Try to Click me!";
btn.Visible=true;
this.Controls.Add(btn);
}
public static void Main()
{
//let's put some filter on our Application's message queue
  Application.AddMessageFilter(new MyFilter());
//create the MainForm object and make it visible
  Application.Run(new MainForm());
}
}