通过监听Windows消息实现控件的键盘和鼠标事件路由

      以前发表过《通过监听Windows消息对复合控件进行整体控制(C#)一 》两篇，讲述了通过FrameWork框架提供的技术监听Windows消息来实现事件的路由，但部分实现并不是很好，而且有部分功能并不能很好解决控件的事件，此篇通过对原方法进行改写，有些实现通过调用Windows API辅助解决，基本上解决了控件的键盘和鼠标事件的路由。（JS和WPF有事件路由的功能）

      实现 IMessageFilter 接口 和 注册控件的鼠标和键盘事件等对外接口请参考《通过监听Windows消息对复合控件进行整体控制(C#)一 》，内部的实现通过使用Windows API 使代码更严谨和清晰。

      使用到的部分API方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace LC.Windows.MessageListen
{
    class Win32API
    {
        //static public long Count;
        #region  常量及开源

        public const int WM_KEYDOWN = 0x100;
        public const int WM_SYSKEYDOWN = 0x104;
        public const int WM_KEYUP = 0x101;
        public const int WM_SYSKEYUP = 0x105;
        public const int WM_MOUSEMOVE = 0x200;
        public const int WM_MOUSEHOVER = 0x2a1;
        public const int WM_MOUSELEAVE = 0x2a3;
        public const int WM_LBUTTONDOWN = 0x201;
        public const int WM_LBUTTONUP = 0x202;
        public const int WM_LBUTTONDBLCLK = 0x203;
        public const int WM_RBUTTONDOWN = 0x204;
        public const int WM_RBUTTONUP = 0x205;
        public const int WM_RBUTTONDBLCLK = 0x206;
        public const int WM_NCMOUSEMOVE = 0xa0;
        public const int WM_NCLBUTTONDOWN = 0xa1;
        public const int WM_NCLBUTTONUP = 0xa2;
        public const int WM_MOUSEWHEEL = 0x20a;
        public const int WM_PAINT = 0xf;
        public const int WM_TIMER = 0x113;

        //----------开源代码----------------------
        int zDelta;

        public const int MK_LBUTTON = 0x0001;
        public const int MK_RBUTTON = 0x0002;
        public const int MK_SHIFT = 0x0004;
        public const int MK_CONTROL = 0x0008;
        public const int MK_MBUTTON = 0x0010;
        public const int MK_XBUTTON1 = 0x0020;
        public const int MK_XBUTTON2 = 0x0040;
        public static int GetXLParam(int lparam) { return LowWord(lparam); }
        public static int GetYLParam(int lparam) { return HighWord(lparam); }
        public static int LowWord(int word) { return word & 0xFFFF; }
        public static int HighWord(int word) { return word >> 16; }
        public static int GetWheelDeltaWParam(int wparam) { return HighWord(wparam); }
        public static MouseButtons GetMouseButtonWParam(int wparam)
        {
            int mask = LowWord(wparam);

            if ((mask & MK_LBUTTON) == MK_LBUTTON) return MouseButtons.Left;
            if ((mask & MK_RBUTTON) == MK_RBUTTON) return MouseButtons.Right;
            if ((mask & MK_MBUTTON) == MK_MBUTTON) return MouseButtons.Middle;
            if ((mask & MK_XBUTTON1) == MK_XBUTTON1) return MouseButtons.XButton1;
            if ((mask & MK_XBUTTON2) == MK_XBUTTON2) return MouseButtons.XButton2;

            return MouseButtons.None;
        }


        public MouseButtons GetMouseUpMouseButtons(int msg)
        {
            if (msg == WM_LBUTTONUP)
                return MouseButtons.Left;
            else if (msg == WM_RBUTTONUP)
                return MouseButtons.Right;
            else
                return MouseButtons.None;
        }



        public const int CWP_ALL = 0x0000;
        public const int CWP_SKIPINVISIBLE = 0x0001;
        public const int CWP_SKIPDISABLED = 0x0002;
        public const int CWP_SKIPTRANSPARENT = 0x0004;

        public const uint TME_HOVER = 0x00000001;
        public const uint TME_LEAVE = 0x00000002;
        public const uint TME_QUERY = 0x40000000;
        public const uint TME_CANCEL = 0x80000000;

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int ShowCursor(bool isShow);
        
        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int GetCapture();

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int SetCapture(IntPtr hWnd);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern bool ReleaseCapture();

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern bool GetCursorPos(ref POINT pos);    //如果POINT是class 就不能加ref

        //取出客户端的矩形，相对于控件自身。
        [System.Runtime.InteropServices.DllImport("user32.dll")]
        private static extern bool GetClientRect(int hwnd, [In, Out]ref RECT rect);


        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern bool PtInRect(ref RECT rect, POINT pos);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int ChildWindowFromPointEx(int hwnd, POINT pos, uint un);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern bool ClientToScreen(int hwnd, ref POINT pos);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern bool ScreenToClient(int hwnd, ref POINT pos);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern bool IsChild(int hWndParent, int hWnd);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int MapWindowPoints(int hWndFrom, int hWndTo, ref POINT point, int count);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int WindowFromPoint(POINT point);

        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int TrackMouseEvent(ref MouseTrackEvent trackEvent);

        //获取窗口标题
        [DllImport("user32", SetLastError = true)]
        public static extern int GetWindowText(
        int hWnd, //窗口句柄
        StringBuilder lpString, //标题
        int nMaxCount //最大值
        );

        //获取类的名字
        [DllImport("user32.dll")]
        private static extern int GetClassName(
        int hWnd, //句柄
        StringBuilder lpString, //类名
        int nMaxCount //最大值
        );

        ////根据坐标获取窗口句柄
        //[DllImport("user32")]
        //private static extern IntPtr WindowFromPoint(
        //POINT Point //坐标
        //);

        #endregion


    }

    [StructLayout(LayoutKind.Sequential)]
    public struct POINT
    {
        public int X;
        public int Y;
        public POINT(int x, int y)
        {
            this.X = x;
            this.Y = y;
        }
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct RECT
    {
        public int left;
        public int top;
        public int right;
        public int bottom;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct MouseTrackEvent
    {
        public uint cbSize;
        public uint dwFlags;
        public int hwndTrack;
        public uint dwHoverTime;
    }


}

注册需要监听的控件的事件，并对控件集合进行排序，根据包含关系由子到父进行排序

/// <summary>
        /// 注册一个监听的控件。
        /// </summary>
        /// <param name="wrapper"></param>
        public void Regist(RegistControlWrapper wrapper)
        {
            lock (m_lckObj)
            {
                m_RegistControls[wrapper.Handle] = wrapper;
                //对集合进行包含性排序，即把子的排在前面
                //对集合进行包含性排序，即把子的排在前面
                m_KeyValuePairControls.Clear();
                if (m_RegistControls.Count >= 2)    //大于2就进行排序。
                    m_KeyValuePairControls = m_RegistControls.OrderBy(p => p, new ContainSubCtrlComparer<KeyValuePair<int, RegistControlWrapper>>()).ToList();
                else if (m_RegistControls.Count == 1)
                    m_KeyValuePairControls = new List<KeyValuePair<int, RegistControlWrapper>>(m_RegistControls);

                if (m_RegistControls.Count == 1)
                {
                    Application.AddMessageFilter(this);
                }
            }
        }

在处理鼠标事件中，最麻烦的是鼠标进入事件和离开事件，由于IMessageFilter对进程外的其他进程的消息是监听不了的，而鼠标离开事件并不能根据WM_MOUSELEAVE 消息进行即时的处理，因此，必需更好的使用API才能实现。

使用GetCursorPos获取当前光标的位置，然后通过WindowFromPoint获取光标对应的控件的句柄，再由IsChild判断句柄是否在订阅的控件里来决定鼠标是否完全离开该控件，对于由于进入子控件而产生的WM_MOUSELEAVE 消息，还得在合适的时机调用TrackMouseEvent，以使该控件下次能再次发出WM_MOUSELEAVE 消息。

  /// <summary>
        /// 处理鼠标离开事件。
        /// </summary>
        /// <param name="m"></param>
        /// <param name="isCancel"></param>
        private void ProcessMouseLeave(ref Message m, ref bool cancel)
        {
            ////如果是本集成的子控件导致顶层控件产生MouseLeave事件的，将屏闭该消息。

            int handle = m.HWnd.ToInt32();
            if (GetTopParenRegistControl(handle) > 0)
            {
                //获取当前光标的位置下的控件是否为该控件的子
                POINT pt = new POINT();
                Win32API.GetCursorPos(ref pt);       //屏幕

                //获取当前屏幕点下的控件
                int newHandle = Win32API.WindowFromPoint(pt);

                if (newHandle == m_CacheEntry.ParentHandle || Win32API.IsChild(m_CacheEntry.ParentHandle, newHandle))
                {
                    if (m_CacheEntry.CurrentHandle == m_CacheEntry.ParentHandle)
                    {
                        cancel = true;      //不做离开事件。如要下次再发出WM_MOUSELEAVE消息，得执行TrackMouseEvent方法（每调用些方法一次，才发出一次WM_MOUSELEAVE消息。）
                        m_CacheEntry.ControlWrapper.IsTrackLeave = false;
                    }
                }
                else
                {
                    //真正的退出

                    //不做嵌套的控件的退出，觉得没有意义
                    //SetLeaveFlags(ref cancel);
                    //RaiseAllMouseLeaveEvent(m_CacheEntry.CurrentHandle);

                    if (m_CacheEntry.CurrentHandle == m_CacheEntry.ParentHandle)
                    {
                        m_CacheEntry.ControlWrapper.IsTrackLeave = false;
                    }
                    else
                        RaiseMouseLeaveEvent(m_CacheEntry.ParentHandle);         //做多处离去事件，由里往外， 不知进入的是否要多处的需求（由外往里）？

                    m_CacheEntry.CurrentHandle = 0;
                    m_CacheEntry.ParentHandle = 0;
                }


             }

        }

在这个版本中，严谨度和清晰度大大提高，完全解决鼠标离开的消息，但调试中发现鼠标进入事件有时多执行一次，考虑到实现开发中多执行一次进入事件，影响不大，这个小Bug留真正有需要解决的读者去完成，下面的完整的代码，仅供学习。

/Files/Yjianyong/MessageListener.rar