[jiangsheng大哥帮忙]WebBrowser窗口子类化bug(up有分)

环境：VS2005 C# WinForm XPSP2 IE8 -- 另注：电脑硬件绝对没问题


问题起因：

WebBrowser控件在重绘时(比如它被从容器底部提到了顶部)。先是重绘背景，然后再绘制内容。重绘背景不仅多余而且造成闪烁。在VC中，只需屏蔽WM_ERASEBKGND消息即可消除闪烁。但是在C#中，试图通过重载WebBrowser自己的WndProc去捕获WM_ERASEBKGND是行不通的。可行办法是通过查找Internet Explorer_Server窗口然后进行窗口子类化。这样才能捕获到WM_ERASEBKGND。

       using PARAM = System.IntPtr;

       using MESSAGE = System.Int32;

       using RETURN = System.Int32;

       ////////////////////////////////



        [DllImport("user32.dll")]

        protected static extern IntPtr GetWindowLong(int hwindow, int unindex);



        [DllImport("user32.dll")]

        static extern RETURN CallWindowProc(IntPtr lpPrevWndFunc, IntPtr hWnd, MESSAGE Msg, PARAM wParam, PARAM lParam);



        [DllImport("user32.dll")]

        protected static extern int SetWindowLong(int hwindow, int unindex, WndProcDelegate lnewvalue);



        private void Form1_Load(object sender, EventArgs e)

        {

            this.webBrowser1.Navigate("http://www.google.com.hk/");

            this.webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);//必需在文档加载完后才能查找窗口成功

        }



        bool add = false;

        IntPtr oldWindow = IntPtr.Zero;

        const int GWL_WNDPROC = -4;

        public delegate RETURN WndProcDelegate(IntPtr hWnd, MESSAGE msg, PARAM wParam, PARAM lParam);

        public WndProcDelegate MyCallWindowProc;



        void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)

        {

            if(add)

            { return; }

            add = true;

            FindWindow fw = new FindWindow(this.Handle, "Internet Explorer_Server");

            IntPtr hIE = fw.FoundHandle;



            if (hIE.ToInt32() != 0)

            {

                oldWindow = GetWindowLong(hIE.ToInt32(), GWL_WNDPROC);

                MyCallWindowProc = new WndProcDelegate(WndProc);

                SetWindowLong(hIE.ToInt32(), GWL_WNDPROC, MyCallWindowProc);

            }

        }



        public RETURN WndProc(IntPtr hWnd, MESSAGE Msg, PARAM WParam, PARAM LParam)

        {

            const int WM_ERASEBKGND = 0x14;



            if (Msg == WM_ERASEBKGND)

            {

                return  1;

            }



            return CallWindowProc(oldWindow, hWnd, Msg, WParam, LParam);

        }



    class FindWindow

    {

        [DllImport("user32")]

        [return: MarshalAs(UnmanagedType.Bool)]

        //IMPORTANT : LPARAM  must be a pointer (InterPtr) in VS2005, otherwise an exception will be thrown

        private static extern bool EnumChildWindows(IntPtr window, EnumWindowProc callback, IntPtr i);

        //the callback function for the EnumChildWindows

        private delegate bool EnumWindowProc(IntPtr hWnd, IntPtr parameter);



        //if found  return the handle , otherwise return IntPtr.Zero

        [DllImport("user32.dll", EntryPoint = "FindWindowEx")]

        private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);



        private string m_classname; // class name to look for



        private IntPtr m_hWnd; // HWND if found

        public IntPtr FoundHandle

        {

            get { return m_hWnd; }

        }

        // ctor does the work--just instantiate and go

        public FindWindow(IntPtr hwndParent, string classname)

        {

            m_hWnd = IntPtr.Zero;

            m_classname = classname;

            FindChildClassHwnd(hwndParent, IntPtr.Zero);

        }



        private bool FindChildClassHwnd(IntPtr hwndParent, IntPtr lParam)

        {

            EnumWindowProc childProc = new EnumWindowProc(FindChildClassHwnd);

            IntPtr hwnd = FindWindowEx(hwndParent, IntPtr.Zero, this.m_classname, string.Empty);

            if (hwnd != IntPtr.Zero)

            {

                this.m_hWnd = hwnd; // found: save it

                return false; // stop enumerating

            }

            EnumChildWindows(hwndParent, childProc, IntPtr.Zero); // recurse  redo FindChildClassHwnd

            return true;// keep looking

        }

    }

使用以上方法，webBrowser在重绘时不再擦除背景。但没料到的是，出现了这样一个bug：

在打开中文输入法情况下，一些标点符号无法输入到网页上的编辑框里。包括"；‘，。"等等。但输入汉字没问题，英文(标点)也没问题。

测试发现，一次按键（标点符号键），WndProc收到了正确的WM_KEYDOWN及WM_KEYUP消息。但没有收到WM_IME_CHAR。收到了两个WM_CHAR，但不论是单独还是组合起来，都和按键内容没有任何关联。


我找不出我代码中有什么错误，估计这又是C#的一个bug。欢迎大家给出建议或帮忙顶贴。并盼JinagSheng大哥能再次给出指点。如果是确实是C#的bug，能否向微软反应？