http://blog.csdn.net/xochenlin/article/details/4328954

 

C# Winform中WndProc 函数作用：

主要用在拦截并处理系统消息和自定义消息

比如:

windows程序会产生很多消息，比如你单击鼠标，移动窗口都会产生消息。这个函数就是默认的消息处理函数。你可以重载这个函数来制定自己的消息处理流程.

在Winform程序中，可以重写WndProc函数，来捕捉所有发生的窗口消息。

这样，我们就可以"篡改"传入的消息，而人为的让窗口改变行为。

简单测试代码： 

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;using System.Runtime.InteropServices;namespace ControlTest{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        private Demo demo = null;        private void Form1_Load(object sender, EventArgs e)        {            //demo = new Demo(this.Handle.ToInt32());        }        private void button1_Click(object sender, EventArgs e)        {            demo = new Demo(this.Handle.ToInt32());            demo.Test();        }        protected override void WndProc(ref Message m)        {            if (m.Msg == Demo.MY_MSG_BEGIN)            {                MessageBox.Show("类Demo for循环开始.");            }            else if (m.Msg == Demo.MY_MSG_END)            {                MessageBox.Show("类Demo for循环结束.");            }            base.WndProc(ref m);        }    }    public class Demo    {        private int m_hWnd = 0;        public Demo(int hWnd)        {            m_hWnd = hWnd;        }        private const int WM_USER = 0x0400;        public static int MY_MSG_BEGIN = WM_USER + 100;        public static int MY_MSG_END = WM_USER + 101;        [DllImport("User32.DLL")]        public static extern int SendMessage(int hWnd, int Msg, int wParam, int lParam);        public void Test()        {            SendMessage(m_hWnd, MY_MSG_BEGIN, 0, 0);            for (int i = 0; i < 100000; i++)            {                Application.DoEvents();            }            SendMessage(m_hWnd, MY_MSG_END, 0, 0);        }    }   }