键盘钩子lParam问题

Question

if (lParam & 0x80000000)判断让键盘只处理一次事件，
网上资料好像可行 ，为什么我提示错误
运算符“&”无法应用于“System.IntPtr”和“uint”类型的操作数。

Answer 1

if ((lParam.ToInt64() & 0x80000000) == 0x80000000)

Answer 2

       //钩子事件内部调用,调用_clientMethod方法转发到客户端应用。 
        private static int OnHookProc(int nCode, int wParam, IntPtr lParam)
        {
            if ((lParam.ToInt64 ()& 0x80000000) == 0x80000000)
            {                {
                    if (nCode >= 0)
                    {                        //转换结构 
                        HookStruct hookStruct = (HookStruct)Marshal.PtrToStructure(lParam, typeof(HookStruct));                        if (_clientMethod != null)
                        {
                            bool handle = false;
                            //调用客户提供的事件处理程序。 
                            _clientMethod(hookStruct, out handle);
                            if (handle)
                                return 1; //1:表示拦截键盘,return 退出 
                        }
                    }
                }
                return CallNextHookEx(_hHookValue, nCode, wParam, lParam);
            }提示错误  “Vjsdn.Tech.KeyboardHook.KeyboardHookLib.OnHookProc(int, int, System.IntPtr)”: 并非所有的代码路径都返回值

Answer 3

private static int OnHookProc(int nCode, int wParam, IntPtr lParam)
{
    if ((lParam.ToInt64() & 0x80000000) == 0x80000000)
    {
        if (nCode >= 0)
        {
            //转换结构  
            HookStruct hookStruct = (HookStruct)Marshal.PtrToStructure(lParam, typeof(HookStruct));
            if (_clientMethod != null)
            {
                bool handle = false;
                //调用客户提供的事件处理程序。  
                _clientMethod(hookStruct, out handle);
                if (handle)
                    return 1; //1:表示拦截键盘,return 退出  
            }
        }
    }
    return CallNextHookEx(_hHookValue, nCode, wParam, lParam);
}

Answer 4

  if ((lParam.ToInt64() & 0x80000000) == 0x80000000) 这句我这里0x80000000的颜色都是黑的，应该是这有问题，0x80000000应该是32位，是不是缺少引用，还是不太理解

Answer 5

键盘钩子类
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Reflection;
using System.Diagnostics;
using Microsoft.Win32;
using System.Windows.Forms;namespace Vjsdn.Tech.KeyboardHook
{
    /// <summary> 
    /// 键盘Hook管理类, by www.vjsdn.com 易学原创 
    /// </summary> 
    public class KeyboardHookLib
    {
        private const int WH_KEYBOARD_LL = 13; //键盘         //键盘处理事件委托 ,当捕获键盘输入时调用定义该委托的方法. 
        private delegate int HookHandle(int nCode, int wParam, IntPtr lParam);        //客户端键盘处理事件 
        public delegate void ProcessKeyHandle(HookStruct param, out bool handle);        //接收SetWindowsHookEx返回值 
        private static int _hHookValue = 0;        //勾子程序处理事件 
        private HookHandle _KeyBoardHookProcedure;        //Hook结构 
        [StructLayout(LayoutKind.Sequential)]
        public class HookStruct
        {
            public int vkCode;
            public int scanCode;
            public int flags;
            public int time;
            public int dwExtraInfo;
        }        //设置钩子 
        [DllImport("user32.dll")]
        private static extern int SetWindowsHookEx(int idHook, HookHandle lpfn, IntPtr hInstance, int threadId);        //取消钩子 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        private static extern bool UnhookWindowsHookEx(int idHook);        //调用下一个钩子 
        [DllImport("user32.dll")]
        private static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);        //获取当前线程ID 
        [DllImport("kernel32.dll")]
        private static extern int GetCurrentThreadId();        //Gets the main module for the associated process. 
        [DllImport("kernel32.dll")]
        private static extern IntPtr GetModuleHandle(string name);        private IntPtr _hookWindowPtr = IntPtr.Zero;        //构造器 
        public KeyboardHookLib() { }        //外部调用的键盘处理事件 
        private static ProcessKeyHandle _clientMethod = null;        /// <summary> 
        /// 安装勾子 
        /// </summary> 
        /// <param name="hookProcess">外部调用的键盘处理事件</param> 
        public void InstallHook(ProcessKeyHandle clientMethod)
        {
            _clientMethod = clientMethod;            // 安装键盘钩子 
            if (_hHookValue == 0)
            {
                _KeyBoardHookProcedure = new HookHandle(OnHookProc);                _hookWindowPtr = GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName);                _hHookValue = SetWindowsHookEx(
                WH_KEYBOARD_LL,
                _KeyBoardHookProcedure,
                _hookWindowPtr,
                0);                //如果设置钩子失败. 
                if (_hHookValue == 0) UninstallHook();
            }
        }        //取消钩子事件 
        public void UninstallHook()
        {
            if (_hHookValue != 0)
            {
                bool ret = UnhookWindowsHookEx(_hHookValue);
                if (ret) _hHookValue = 0;
            }
        }        //钩子事件内部调用,调用_clientMethod方法转发到客户端应用。            private static int OnHookProc(int nCode, int wParam, IntPtr lParam)
{ if ((lParam.ToInt32() & 0x80000000) == 0x80000000)
    {        if (nCode >= 0)
        {
            //转换结构  
            HookStruct hookStruct = (HookStruct)Marshal.PtrToStructure(lParam, typeof(HookStruct));
            if (_clientMethod != null)
            {
                bool handle = false;
                //调用客户提供的事件处理程序。  
                _clientMethod(hookStruct, out handle);
                if (handle)
                    return 1; //1:表示拦截键盘,return 退出  
            }
        }
    }
    return CallNextHookEx(_hHookValue, nCode, wParam, lParam);
}
        }
    }
主界面
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using Vjsdn.Tech.KeyboardHook;
using System.IO;namespace ProjectWarHelp
{
    public partial class Record : Form
    {
        private KeyboardHookLib _keyboardHook = null;
        public Record()
        {
            InitializeComponent();
        }        private void btnOpen_Click(object sender, EventArgs e)
        {
            lblState.Text = "数据记录中。。";
            lblState.ForeColor = Color.Red;
            _keyboardHook = new KeyboardHookLib();
            _keyboardHook.InstallHook(OnKeyPress);
        }        private void btnClose_Click(object sender, EventArgs e)
        {
            lblState.Text = "数据记录中断";
            lblState.ForeColor = Color.SaddleBrown;
            if (_keyboardHook != null)
                _keyboardHook.UninstallHook();
        }
        public void OnKeyPress(KeyboardHookLib .HookStruct hookStruct,out bool handle)
        {
                   handle = false;
                Keys key = (Keys)hookStruct.vkCode;
                FileStream fs = new FileStream(Application.StartupPath + @"\Record.txt", FileMode.Open);
                StreamWriter sw = new StreamWriter(fs);
                sw.BaseStream.Seek(0, SeekOrigin.End);
                sw.Write(key.ToString() + " ");
                sw.Close();
            
        }        private void Record_Load(object sender, EventArgs e)
        {
            lblState.Text = "数据记录中断";
            lblState.ForeColor = Color.SaddleBrown;
            if (!File.Exists(Application.StartupPath + @"\Record.txt"))
            {
                FileStream fs = new FileStream(Application.StartupPath + @"\Record.txt", FileMode.CreateNew);
                fs.Close();
            }
            FileStream fs2 = new FileStream(Application.StartupPath + @"\Record.txt", FileMode.Open);
            StreamWriter sw = new StreamWriter(fs2);
            sw.BaseStream.Seek(0, SeekOrigin.End);
            sw.WriteLine("");
            sw.WriteLine("开始时间："+System .DateTime .Now .ToString ());
            sw.Close();
        }        private void Record_FormClosing(object sender, FormClosingEventArgs e)
        {
            FileStream fs = new FileStream(Application.StartupPath + @"\Record.txt", FileMode.Open);
            StreamWriter sw = new StreamWriter(fs);
            sw.BaseStream.Seek(0, SeekOrigin.End);
            sw.WriteLine("");
            sw.WriteLine("结束时间："+System.DateTime.Now.ToString());
            sw.Close();
        }
    }
}
问题还是解决不了private static int OnHookProc(int nCode, int wParam, IntPtr lParam)运行2次
 加if ((lParam.ToInt32() & 0x80000000) == 0x80000000)这一直不能达到效果，lparam的32位一直是0，keyyon，keydown不是lparam的32位值会改变，问题到底出在哪，头都爆了。