在C#中实现消息过滤

In C# we can filter our application@#s messages so some of them don@#t get dispatched. See the example below of how to prevent the user from clicking the Left Mouse button in our application:

// 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 aclearcase/" target="_blank" >ccepted!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());
}
}

原文转自：http://www.ltesting.net