C# 窗口过程消息处理 WndProc的方法详解

protected override void WndProc(ref Message m)
{
    const int WM_CLOSE = 0x0010;
    if(m.Msg == WM_CLOSE)
    {
        // MessageBox.Show("禁止关闭此窗口");
        return;
    }
    base.WndProc(ref m);
}

HwndSource source = null;
protected override void OnSourceInitialized(EventArgs e)
{
    base.OnSourceInitialized(e);
    IntPtr handle = new WindowInteropHelper(this).Handle;
    source = HwndSource.FromHandle(handle);
    source.AddHook(WndProc);
}
protected override void OnClosed(EventArgs e)
{
    source?.RemoveHook(WndProc);
    base.OnClosed(e);
}
private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    const int WM_CLOSE = 0x0010;
    if(msg == WM_CLOSE)
    {
        // MessageBox.Show("禁止关闭此窗口");
        handled = true; // 标记为已处理
    }
    return IntPtr.Zero;
}

static class Program
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        var filter = new SampleMsgFilter();
        Application.AddMessageFilter(filter); // 添加到消息泵
        Application.Run(new MainForm());
        Application.RemoveMessageFilter(filter); // 从消息泵移除
    }
}
sealed class SampleMsgFilter : IMessageFilter
{
    public bool PreFilterMessage(ref Message m)
    {
        const int WM_MOUSEHOVER = 0x02A1;
        if(m.Msg == WM_MOUSEHOVER && Control.FromHandle(m.HWnd) is Control ctr)
        {
            ctr.FindForm().Text = ctr.Name;
            return true; // 过滤消息不继续派发
        }
        return false; // 允许消息派发到下一个过滤器或控件
    }
}

using System;
using System.Collections.Generic;
using System.Windows.Forms;
namespace Wondershare.WinTool.Helpers
{
  public delegate bool HookProc(ref Message m);
    public static class MessageHooker
    {
        sealed class HookWindow : NativeWindow
        {
            List<KeyValuePair<HookProc, Action>> hooks;
            public HookWindow(IntPtr hWnd)
            {
                AssignHandle(hWnd);
            }
            public void AddHookProc(HookProc hook, Action removedHandler)
            {
                if (hooks == null)
                {
                    hooks = new List<KeyValuePair<HookProc, Action>>();
                }
                hooks.Insert(0, new KeyValuePair<HookProc, Action>(hook, removedHandler));
            }
            public void RemoveHookProc(HookProc hook)
            {
                if (hooks != null)
                {
                    for (int i = hooks.Count - 1; i >= 0; i--)
                    {
                        if (hooks[i].Key == hook)
                        {
                            hooks[i].Value?.Invoke();
                            hooks.RemoveAt(i);
                        }
                    }
                }
            }
            protected override void WndProc(ref Message m)
            {
                if (hooks != null)
                {
                    foreach (var hook in hooks)
                    {
                        if (hook.Key(ref m)) return;
                    }
                    const int WM_NCDESTORY = 0x0082;
                    if (m.Msg == WM_NCDESTROY) // 窗口销毁时移除所有 hook
                    {
                        for (int i = hooks.Count - 1; i >= 0; i--)
                        {
                            hooks[i].Value?.Invoke();
                        }
                        hooks = null;
                    }
                    base.WndProc(ref m);
                }
            }
        }
        /// <summary>附加消息处理过程到窗口</summary>
        /// <param name="handle">需要附加消息处理过程的窗口句柄</param>
        /// <param name="hook">消息处理过程</param>
        /// <param name="removedHandler">消息处理过程移除回调</param>
        public static void AddHook(IntPtr handle, HookProc hook, Action removedHandler = null)
        {
            if (!(NativeWindow.FromHandle(handle) is HookWindow window))
            {
                window = new HookWindow(handle);
            }
            window.AddHookProc(hook, removedHandler);
        }
        /// <summary>从窗口移除附加的消息处理过程</summary>
        /// <param name="handle">需要移除消息处理过程的窗口句柄</param>
        /// <param name="hook">消息处理过程</param>
        public static void RemoveHook(IntPtr handle, HookProc hook)
        {
            if (NativeWindow.FromHandle(handle) is HookWindow window)
            {
                window.RemoveHookProc(hook);
            }
        }
    }
}