一个关于钩子链是否会破坏消息循环的尝试

本人对钩子进行了研究，发现执行钩子函数后会破坏消息循环：具体情况如下，下面源代码中，钩子函数实现的功能是屏蔽按键并在一个TEXTBOX中显示ABC，然而我又在这个TEXTBOX添加了一个键盘按下事件（执行弹出一个提示框），我的测试目的是看下执行完钩子函数后，是否会接着执行这个TEXTBOX上的键盘事件。事实证明，在TEXTBOX中显示ABC后并没有弹出提示框，所以我认为安装钩子会影响到消息循环，不知道我的这个测试结果有什么错误没，或者我在理解钩子上有误差，请各位积极讨论并指点。还有一个问题是我把SETWINDOWSHOOKEX函数的最后一个参数设为0后会抛出异常，提示安装钩子失败，我记得那是设置全局钩子的啊 怎么会错呢？
public partial class Form1 : Form
    {
        // 安装钩子
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
        // 卸载钩子
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern bool UnhookWindowsHookEx(int idHook);
        // 继续下一个钩子
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);
        // 取得当前线程编号
        [DllImport("kernel32.dll")]
        static extern int GetCurrentThreadId();        public delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);
        static int hKeyboardHook = 0;
        HookProc KeyboardHookProcedure;
        private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
        {
            if (nCode >= 0)
            {
                textBox1.Text = "ABC";
                return 1;
            }
            return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);
        }        // 安装钩子
        public void HookStart()
        {
            if (hKeyboardHook == 0)
            {
                // 创建HookProc实例
                KeyboardHookProcedure = new HookProc(KeyboardHookProc);
                // 设置线程钩子
                hKeyboardHook = SetWindowsHookEx(2, KeyboardHookProcedure, IntPtr.Zero,GetCurrentThreadId()
                                            );/*GetCurrentThreadId()*/
                
                // 如果设置钩子失败
                if (hKeyboardHook == 0)
                {
                    HookStop();
                    throw new Exception("SetWindowsHookEx failed.");
                }
            }
        }
        // 卸载钩子
        public void HookStop()
        {
            bool retKeyboard = true;
            if (hKeyboardHook != 0)
            {
                retKeyboard = UnhookWindowsHookEx(hKeyboardHook);
                hKeyboardHook = 0;
            }
            if (!(retKeyboard && retKeyboard)) throw new Exception("UnhookWindowsHookEx failed.");
        }
        public Form1()
        {
            InitializeComponent();
            this.HookStart();        }        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            this.HookStop();
        }        private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            MessageBox.Show("key press");
        }
    }