使用钩子拦截鼠标消息，计算坐标出错

Question

我定义了一个静态类Hook,封装了一下几个API函数
GetCurrentThreadId;
SetWindowsHookEx;
CallNextHookEx
UnhookWindowsHookEx
并且定义了委托
public delegate IntPtr HookProc(int code, IntPtr wparam, IntPtr lparam)然后，将SetHook函数添加到Form的OnLoad方法中
public void SetHook()
{
    if (this._nextHookPtr == IntPtr.Zero)
    {
        this._nextHookPtr = Hook.SetWindowsHookEx(
            (int)HookType.WH_MOUSE,
            new HookProc(MyHookProc),
            IntPtr.Zero, Hook.GetCurrentThreadId());
    }
}IntPtr MyHookProc(int code, IntPtr wparam, IntPtr lparam)
{
    if (code < 0)
    {
        return Hook.CallNextHookEx(this._nextHookPtr, code, wparam, lparam);
    }    if (wparam.ToInt32() == 0x0200) //WM_MOUSEMOVE
    {
        int param = lparam.ToInt32();
        int x = param & 0x0000FFFF; // 取出LPARAM的低字节
        int y = param >> 16; // 取出LPARAM的高字节        this.Xtext.Text = x.ToString(); // Xtext是一个TextBox控件
        this.Ytext.Text = y.ToString();// Ytext是一个TextBox控件
    }    return (IntPtr)0;
}我在窗口中移动鼠标，钩子的确捕获了鼠标移动消息，但是计算出来的坐标是错误的，事实上，当我移动鼠标，X和Y的值基本不变。请高手指点，感激不尽！

Answer 1

要获取鼠标坐标可不用“钩子”
摘录：《程序员秘书》－－源代码－－鼠标和键盘－－获取和设置鼠标位置
textBox1.Text = Cursor.Position.X.ToString() + "，" + Cursor.Position.Y.ToString();//鼠标当前位置
立即成为编程经验丰富的程序员不是梦，详见：http://www.psec.net.cn

Answer 2

鼠标位置是那样捕捉的么?看看这个private int MouseHookProc(int nCode, int wParam, IntPtr lParam)
        {
            // if ok and someone listens to our events
            if ((nCode >= 0) && (OnMouseActivity != null))
            {
                //Marshall the data from callback.
                MouseLLHookStruct mouseHookStruct = (MouseLLHookStruct)Marshal.PtrToStructure(lParam, typeof(MouseLLHookStruct));                //detect button clicked
                MouseButtons button = MouseButtons.None;
                short mouseDelta = 0;
                switch (wParam)
                {
                    case WM_LBUTTONDOWN:
                        //case WM_LBUTTONUP: 
                        //case WM_LBUTTONDBLCLK: 
                        button = MouseButtons.Left;
                        break;
                    case WM_RBUTTONDOWN:
                        //case WM_RBUTTONUP: 
                        //case WM_RBUTTONDBLCLK: 
                        button = MouseButtons.Right;
                        break;
                    case WM_MOUSEWHEEL:
                        //If the message is WM_MOUSEWHEEL, the high-order word of mouseData member is the wheel delta. 
                        //One wheel click is defined as WHEEL_DELTA, which is 120. 
                        //(value >> 16) & 0xffff; retrieves the high-order word from the given 32-bit value
                        mouseDelta = (short)((mouseHookStruct.mouseData >> 16) & 0xffff);
                        //TODO: X BUTTONS (I havent them so was unable to test)
                        //If the message is WM_XBUTTONDOWN, WM_XBUTTONUP, WM_XBUTTONDBLCLK, WM_NCXBUTTONDOWN, WM_NCXBUTTONUP, 
                        //or WM_NCXBUTTONDBLCLK, the high-order word specifies which X button was pressed or released, 
                        //and the low-order word is reserved. This value can be one or more of the following values. 
                        //Otherwise, mouseData is not used. 
                        break;
                }                //double clicks
                int clickCount = 0;
                if (button != MouseButtons.None)
                    if (wParam == WM_LBUTTONDBLCLK || wParam == WM_RBUTTONDBLCLK) clickCount = 2;
                    else clickCount = 1;                //generate event 
                 MouseEventArgs e = new MouseEventArgs(
                                                    button,
                                                    clickCount,
                                                    mouseHookStruct.pt.x,
                                                    mouseHookStruct.pt.y,
                                                    mouseDelta);
                //raise it
                OnMouseActivity(this, e);
            }
            //call next hook
            return CallNextHookEx(hMouseHook, nCode, wParam, lParam);
        }

Answer 3

一些要用到的Struct以及Event:        public event MouseEventHandler OnMouseActivity;        [StructLayout(LayoutKind.Sequential)]
        private class POINT
        {
            public int x;
            public int y;
        }        [StructLayout(LayoutKind.Sequential)]
        private class MouseHookStruct
        {
            public POINT pt;
            public int hwnd;
            public int wHitTestCode;
            public int dwExtraInfo;
        }        [StructLayout(LayoutKind.Sequential)]
        private class MouseLLHookStruct
        {
            public POINT pt;
            public int mouseData;
            public int flags;
            public int time;
            public int dwExtraInfo;
        }