前面兩篇文章講過《通過監聽Windows消息對復合控件進行整體控制》，講述了通過FrameWork框架提供的技術監聽Windows消息來實現事件的路由，但部分實現并不是很好，而且有部分功能并不能很好解決控件的事件，此篇通過對原方法進行改寫，有些實現通過調用Windows API輔助解決，基本上解決了控件的鍵盤和鼠標事件的路由。（JS和WPF有事件路由的功能）

　　實現 IMessageFilter 接口 和 注冊控件的鼠標和鍵盤事件等對外接口請參考《通過監聽Windows消息對復合控件進行整體控制(C#)一 》，內部的實現通過使用Windows API 使代碼更嚴謹和清晰。

　　 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 常量及開源

　　 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;

　　 //----------開源代碼----------------------
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

　　 //取出客戶端的矩形，相對于控件自身。
[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);

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

　　 //獲取類的名字
[DllImport("user32.dll")]
private static extern int GetClassName(
int hWnd, //句柄
StringBuilder lpString, //類名
int nMaxCount //最大值
);

　　 ////根據坐標獲取窗口句柄
//[DllImport("user32")]
//private static extern IntPtr WindowFromPoint(
//POINT Point //坐標
//);

　　 #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;
}

　　}

　　注冊需要監聽的控件的事件，并對控件集合進行排序，根據包含關系由子到父進行排序

　　/// <summary>
/// 注冊一個監聽的控件。
/// </summary>
/// <param name="wrapper"></param>
public void Regist(RegistControlWrapper wrapper)
{
lock (m_lckObj)
{
m_RegistControls[wrapper.Handle] = wrapper;
//對集合進行包含性排序，即把子的排在前面
//對集合進行包含性排序，即把子的排在前面
m_KeyValuePairControls.Clear();
if (m_RegistControls.Count >= 2) //大于2就進行排序。
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);
}
}
}

　　在處理鼠標事件中，最麻煩的是鼠標進入事件和離開事件，由于IMessageFilter對進程外的其他進程的消息是監聽不了的，而鼠標離開事件并不能根據WM_MOUSELEAVE 消息進行即時的處理，因此，必需更好的使用API才能實現。

　　使用GetCursorPos獲取當前光標的位置，然后通過WindowFromPoint獲取光標對應的控件的句柄，再由IsChild判斷句柄是否在訂閱的控件里來決定鼠標是否完全離開該控件，對于由于進入子控件而產生的WM_MOUSELEAVE 消息，還得在合適的時機調用TrackMouseEvent，以使該控件下次能再次發出WM_MOUSELEAVE 消息。

　　/// <summary>
/// 處理鼠標離開事件。
/// </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導致頂層控件產生MouseLeave事件的，將屏閉該消息。

　　 int handle = m.HWnd.ToInt32();
if (GetTopParenRegistControl(handle) > 0)
{
//獲取當前光標的位置下的控件是否為該控件的子
POINT pt = new POINT();
Win32API.GetCursorPos(ref pt); //屏幕

　　 //獲取當前屏幕點下的控件
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; //不做離開事件。如要下次再發出WM_MOUSELEAVE消息，得執行TrackMouseEvent方法（每調用些方法一次，才發出一次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，覺得沒有意義
//SetLeaveFlags(ref cancel);
 //RaiseAllMouseLeaveEvent(m_CacheEntry.CurrentHandle);

　　 if (m_CacheEntry.CurrentHandle == m_CacheEntry.ParentHandle)
{
m_CacheEntry.ControlWrapper.IsTrackLeave = false;
}
else
 RaiseMouseLeaveEvent(m_CacheEntry.ParentHandle); //做多處離去事件，由里往外， 不知進入的是否要多處的需求（由外往里）？

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

　　 }

　　 }

　　鼠標離開的消息處理方法

　　在這個版本中，嚴謹度和清晰度大大提高，完全解決鼠標離開的消息，但調試中發現鼠標進入事件有時多執行一次，考慮到實現開發中多執行一次進入事件，影響不大，這個小Bug留真正有需要解決的讀者去完成，下面的完整的代碼，僅供學習。