诚心请教关于鼠标钩WH_MOUSE_LL的标题栏点击消息（WM_NCLBUTTONDOWN)的问题

Question

程序运行没有任何问题，除了非客户区域的消息，其他的都能捕捉到，WM_LBUTTONDOWN也可以在其他窗口的标题栏上捕捉到。
但现在我想判断鼠标是否在标题栏上点击而不是随意的点击，怎么都捕捉不到WM_NCLBUTTONDOWN消息。MSDN上说这个消息会被所在窗口的进程所捕获，没看明白怎么回事。望指点一下。MouseHookProcedure = new HookProc(MouseHookProc);
            IntPtr pInstance = Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().ManifestModule);
            hMouseHook = SetWindowsHookEx(WH_MOUSE_LL, (HookProc)MouseHookProcedure, pInstance, 0);
            if (hMouseHook == 0)
            {
                MessageBox.Show("SetWindowsHookEx(Mouse) Failed");
                return;
            }
这里有个过去的帖子，里面的问题和我一样，虽然问题解决了却没有答案，郁闷死。
http://topic.csdn.net/t/20010722/15/204237.html#r_1299772

Answer 1

你是怎么做的?
 switch(wParam)  
 {  
   case   WM_NCLBUTTONDOWN:  
}

Answer 2

对，和楼上写得一样
public int MouseHookProc(int nCode, Int32 wParam, IntPtr lParam)
        {
            if (nCode < 0)
            {
                return CallNextHookEx(hMouseHook, nCode, wParam, lParam);
            }            //MyMouseHookStruct = (MouseHookStruct)Marshal.PtrToStructure(lParam, typeof(MouseHookStruct));
            //MyMouseHookStruct.pt.x;
            //MyMouseHookStruct.pt.y;
            //MyMouseHookStruct.mouseData
                        switch (wParam)
            {
                case WM_LBUTTONDOWN:
                    
                    break;
                case WM_LBUTTONUP:
                    
                    break;
                case WM_MOUSEMOVE:
                    
                    break;
                default: break;
            }
            return CallNextHookEx(hMouseHook, nCode, wParam, lParam);
        }

Answer 3

帖子里忘记加这行了，case  WM_NCLBUTTONDOWN:， 但我代码里有，检测不到break；不知道怎么才能得到。查了msdn，有个WM_NCXBUTTONDOWN的消息，不知道有没有用。 

Answer 4

MouseHookProc的代码都贴出来,你怎么检测的?

Answer 5

直接在里面添加一个messagebox.show("done")检测的,就这样。case WM_NCLBUTTONDOWN:
MessageBox.Show("Done!");
break;

Answer 6

case WM_NCLBUTTONDOWN放在switch 的最开始没?

Answer 7

话说我现在也在做鼠标点击消息的hook，我想问的是((PMSLLHOOKSTRUCT)lParam)->pt是屏幕坐标吗？