C# Message处理

可以用2种方法来处理
1. 重载DefWndProc 方法
2. 继承IMessageFilter接口

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

namespace ReceiveMyMessage
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            Application.AddMessageFilter(new MyMessageFilter());
        }

        public const int WM_USER = 0x0400;
        public const int WM_TEST = WM_USER + 1; 
        
        [DllImport("user32", EntryPoint = "SendMessage")]
        public static extern int SendMessage(int hwnd, int msg, int wparam, int lparam);

        private void button1_Click(object sender, EventArgs e)
        {
            SendMessage(Handle.ToInt32(), WM_TEST, 100, 200); 
        }

        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_TEST)
            {
                return;
            }
            base.WndProc(ref m);
        }
    }

    public class MyMessageFilter : IMessageFilter
    {
        public const int WM_USER = 0x0400;
        public const int WM_TEST = WM_USER + 1; 
        public bool PreFilterMessage(ref Message m)
        {
            if (m.Msg == WM_TEST)
            {
                string message = string.Format("收到消息!参数为:{0},{1}", m.WParam, m.LParam);
                MessageBox.Show(message); ///显示一个消息框 
                return true;
            }
            return false;
        } 
    }
}