I'm using a global keyboard hook class. This class allows to check if keyboard key pressed anywhere. And after some time I'm having an error:
**CallbackOnCollectedDelegate was detected**
A callback was made on a garbage collected delegate of type 'Browser!Utilities.globalKeyboardHook+keyboardHookProc::Invoke'. This may cause application crashes, corruption and data loss. When passing delegates to unmanaged code, they must be kept alive by the managed application until it is guaranteed that they will never be called.
Here is globalkeyboardHook class:
public delegate int keyboardHookProc(int code, int wParam, ref keyboardHookStruct lParam);
public struct keyboardHookStruct
{
public int vkCode;
public int scanCode;
public int flags;
public int time;
public int dwExtraInfo;
}
const int WH_KEYBOARD_LL = 13;
const int WM_KEYDOWN = 0x100;
const int WM_KEYUP = 0x101;
const int WM_SYSKEYDOWN = 0x104;
const int WM_SYSKEYUP = 0x105;
public List<Keys> HookedKeys = new List<Keys>();
IntPtr hhook = IntPtr.Zero;
public event KeyEventHandler KeyDown;
public event KeyEventHandler KeyUp;
public globalKeyboardHook()
{
hook();
}
~globalKeyboardHook()
{
unhook();
}
public void hook()
{
IntPtr hInstance = LoadLibrary("User32");
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);
}
public void unhook()
{
UnhookWindowsHookEx(hhook);
}
public int hookProc(int code, int wParam, ref keyboardHookStruct lParam)
{
if (code >= 0)
{
Keys key = (Keys)lParam.vkCode;
if (HookedKeys.Contains(key))
{
KeyEventArgs kea = new KeyEventArgs(key);
if ((wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN) && (KeyDown != null))
{
KeyDown(this, kea);
}
else if ((wParam == WM_KEYUP || wParam == WM_SYSKEYUP) && (KeyUp != null))
{
KeyUp(this, kea);
}
if (kea.Handled)
return 1;
}
}
return CallNextHookEx(hhook, code, wParam, ref lParam);
}
[DllImport("user32.dll")]
static extern IntPtr SetWindowsHookEx(int idHook, keyboardHookProc callback, IntPtr hInstance, uint threadId);
[DllImport("user32.dll")]
static extern bool UnhookWindowsHookEx(IntPtr hInstance);
[DllImport("user32.dll")]
static extern int CallNextHookEx(IntPtr idHook, int nCode, int wParam, ref keyboardHookStruct lParam);
[DllImport("kernel32.dll")]
static extern IntPtr LoadLibrary(string lpFileName);
#endregion
Any ideas how to fix it? The program works well, but after some time the program freezes ant I get this error.
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);
There's your problem. You are relying on C# syntax sugar to have it automatically create a delegate object to hookProc. Actual code generation look like this:
keyboardHookProc $temp = new keyboardHookProc(hookProc);
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, $temp, hInstance, 0);
There's only one reference to the delegate object, $temp. But it is local variable and disappears as soon as your hook() method stops executing and returns. The garbage collector is otherwise powerless to see that Windows has a 'reference' to it as well, it cannot probe unmanaged code for references. So the next time the garbage collector runs, the delegate object gets destroyed. And that's a kaboom when Windows makes the hook callback. The built-in MDA detects the problem and generates the helpful diagnostic before the program crashes with an AccessViolation.
You will need to create an additional reference to the delegate object that survives long enough. You could use GCHandle for example. Or easier, just store a reference yourself so the garbage collector can always see the reference. Add a field to your class. Making it static is a sure-fire way to ensure the object can't be collected:
private static keyboardHookProc callbackDelegate;
public void hook()
{
if (callbackDelegate != null) throw new InvalidOperationException("Can't hook more than once");
IntPtr hInstance = LoadLibrary("User32");
callbackDelegate = new keyboardHookProc(hookProc);
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, callbackDelegate, hInstance, 0);
if (hhook == IntPtr.Zero) throw new Win32Exception();
}
public void unhook()
{
if (callbackDelegate == null) return;
bool ok = UnhookWindowsHookEx(hhook);
if (!ok) throw new Win32Exception();
callbackDelegate = null;
}
No need to pinvoke FreeLibrary, user32.dll is always loaded until your program terminates.
It didn't take too long to get it done!
Here's an all good working implementation with latest fix (definitions & implementations) following Hans Passant's answer and a GitHub project.
//file Win32Api.cs
using System;
using System.Runtime.InteropServices;
using YourProjectNamespace.Hooks;
namespace YourProjectNamespace
{
public delegate int keyboardHookProc(int code, int wParam, ref keyboardHookStruct lParam);
/// <summary>
/// Pcursor info
/// </summary>
[StructLayout(LayoutKind.Sequential)]
public struct PCURSORINFO
{
public Int32 Size;
public Int32 Flags;
public IntPtr Cursor;
public POINTAPI ScreenPos;
}
/// <summary>
/// Point
/// </summary>
[StructLayout(LayoutKind.Sequential)]
public struct POINTAPI
{
public int x;
public int y;
}
/// <summary>
/// keyboard hook struct
/// </summary>
public struct keyboardHookStruct
{
public int dwExtraInfo;
public int flags;
public int scanCode;
public int time;
public int vkCode;
}
/// <summary>
/// Wrapper for windows 32 calls.
/// </summary>
public class Win32Api
{
public const Int32 CURSOR_SHOWING = 0x00000001;
public const int WH_KEYBOARD_LL = 13;
public const int WM_KEYDOWN = 0x100;
public const int WM_KEYUP = 0x101;
public const int WM_SYSKEYDOWN = 0x104;
public const int WM_SYSKEYUP = 0x105;
[DllImport("user32.dll")]
public static extern bool GetCursorInfo(out PCURSORINFO cinfo);
[DllImport("user32.dll")]
public static extern bool DrawIcon(IntPtr hDC, int X, int Y, IntPtr hIcon);
[DllImport("winmm.dll")]
private static extern int mciSendString(string MciComando, string MciRetorno, int MciRetornoLeng, int CallBack);
[DllImport("user32")]
private static extern int GetKeyboardState(byte[] pbKeyState);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern short GetKeyState(int vKey);
[DllImport("user32")]
public static extern int ToAscii(
int uVirtKey,
int uScanCode,
byte[] lpbKeyState,
byte[] lpwTransKey,
int fuState);
[DllImport("user32.dll", CharSet = CharSet.Auto,
CallingConvention = CallingConvention.StdCall)]
public static extern int CallNextHookEx(
IntPtr idHook,
int nCode,
int wParam,
ref keyboardHookStruct lParam);
[DllImport("user32.dll", CharSet = CharSet.Auto,
CallingConvention = CallingConvention.StdCall, SetLastError = true)]
public static extern int UnhookWindowsHookEx(IntPtr idHook);
[DllImport("user32.dll", CharSet = CharSet.Auto,
CallingConvention = CallingConvention.StdCall, SetLastError = true)]
public static extern IntPtr SetWindowsHookEx(
int idHook,
keyboardHookProc lpfn,
IntPtr hMod,
int dwThreadId);
[DllImport("kernel32.dll")]
public static extern IntPtr LoadLibrary(string dllToLoad);
//Constants
} // class Win32
**File GlobalKeyboardHook.cs**
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using log4net;
namespace ScreenRecorder.Hooks
{
public class GlobalKeyboardHook
{
private static readonly ILog log = LogManager.GetLogger(typeof (GlobalKeyboardHook).Name);
const int WH_KEYBOARD_LL = 13;
const int WM_KEYDOWN = 0x100;
const int WM_KEYUP = 0x101;
const int WM_SYSKEYDOWN = 0x104;
const int WM_SYSKEYUP = 0x105;
private static keyboardHookProc callbackDelegate;
public List<Keys> HookedKeys = new List<Keys>();
private IntPtr keyboardHook = IntPtr.Zero;
/// <summary>
public GlobalKeyboardHook()
{
Hook();
}
~GlobalKeyboardHook() {
Unhook();
}
public event KeyEventHandler KeyDown;
public event KeyEventHandler KeyUp;
public int HookProc(int nCode, int wParam, ref keyboardHookStruct lParam)
{
if (nCode >= 0)
{
var key = (Keys) lParam.vkCode;
if (HookedKeys.Contains(key))
{
var kArgs = new KeyEventArgs(key);
if ((wParam == Win32Api.WM_KEYDOWN || wParam == Win32Api.WM_SYSKEYDOWN) && (KeyDown != null))
{
KeyDown(this, kArgs);
}
else if ((wParam == Win32Api.WM_KEYUP || wParam == Win32Api.WM_SYSKEYUP) && (KeyUp != null))
{
KeyUp(this, kArgs);
}
if (kArgs.Handled)
return 1;
}
}
return Win32Api.CallNextHookEx(keyboardHook, nCode, wParam, ref lParam);
}
public void Hook()
{
// Create an instance of HookProc.
//if (callbackDelegate != null) throw new InvalidOperationException("Multiple hooks are not allowed!");
IntPtr hInstance = Win32Api.LoadLibrary("User32");
callbackDelegate = new keyboardHookProc(HookProc);
//install hook
keyboardHook = Win32Api.SetWindowsHookEx( Win32Api.WH_KEYBOARD_LL, callbackDelegate, hInstance, 0);
//If SetWindowsHookEx fails.
if (keyboardHook == IntPtr.Zero)
{
//Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set.
var errorCode = Marshal.GetLastWin32Error();
log.Error("Unable to install keyboard hook.", new Win32Exception(errorCode));
}
}
/// <summary>
/// Unsubscribe for keyboard hook
/// </summary>
public void Unhook()
{
if (callbackDelegate == null) return;
if (keyboardHook != IntPtr.Zero)
{
//uninstall hook
var retKeyboard = Win32Api.UnhookWindowsHookEx(keyboardHook);
//reset invalid handle
keyboardHook = IntPtr.Zero;
//if failed and exception must be thrown
if (retKeyboard == 0)
{
//Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set.
var errorCode = Marshal.GetLastWin32Error();
//Initializes and throws a new instance of the Win32Exception class with the specified error.
log.Error("Error while uninstalling keyboard hook", new Win32Exception(errorCode));
}
}
callbackDelegate = null;
}
}
}
Related
I've been having trouble with a certain problem. I've been disabling left and right mouse clicks for a particular application and my C# code looks like below...
My problem is that even though this works fine for disabling the mouse on a low level, isn't there a way in where I could disable it on a low level just for when the application is focused and therefor running?
using System;
using System.Runtime.InteropServices;
using System.Diagnostics;
namespace GlobalLowLevelHooks
{
public class MouseHook
{
public bool enabled = false;
public delegate IntPtr MouseHookHandler(int nCode, IntPtr wParam, IntPtr lParam);
public MouseHookHandler hookHandler;
public delegate void MouseHookCallback(MSLLHOOKSTRUCT mouseStruct);
#region Events
public event MouseHookCallback LeftButtonDown;
public event MouseHookCallback LeftButtonUp;
public event MouseHookCallback RightButtonDown;
public event MouseHookCallback RightButtonUp;
public event MouseHookCallback MouseMove;
public event MouseHookCallback MouseWheel;
public event MouseHookCallback DoubleClick;
public event MouseHookCallback MiddleButtonDown;
public event MouseHookCallback MiddleButtonUp;
#endregion
public IntPtr hookID = IntPtr.Zero;
public void Enable()
{
hookHandler = HookFunc;
hookID = SetHook(hookHandler);
enabled = true;
}
public void Disable()
{
if (hookID == IntPtr.Zero)
return;
UnhookWindowsHookEx(hookID);
hookID = IntPtr.Zero;
enabled = false;
}
~MouseHook()
{
Enable();
}
private IntPtr SetHook(MouseHookHandler proc)
{
using (ProcessModule module = Process.GetCurrentProcess().MainModule)
return SetWindowsHookEx(WH_MOUSE_LL, proc, GetModuleHandle(module.ModuleName), 0);
}
private IntPtr HookFunc(int nCode, IntPtr wParam, IntPtr lParam)
{
// parse system messages
if (nCode >= 0)
{
if (MouseMessages.WM_LBUTTONDOWN == (MouseMessages)wParam)
{
return (IntPtr)1;
}
if (MouseMessages.WM_RBUTTONDOWN == (MouseMessages)wParam)
{
return (IntPtr)1;
}
if (MouseMessages.WM_MBUTTONDOWN == (MouseMessages)wParam)
{
return (IntPtr)1;
}
if (MouseMessages.WM_LBUTTONDBLCLK == (MouseMessages)wParam)
{
return (IntPtr)1;
}
}
return CallNextHookEx(hookID, nCode, wParam, lParam);
}
#region WinAPI
private const int WH_MOUSE_LL = 14;
private enum MouseMessages
{
WM_LBUTTONDOWN = 0x0201,
WM_LBUTTONUP = 0x0202,
WM_MOUSEMOVE = 0x0200,
WM_MOUSEWHEEL = 0x020A,
WM_RBUTTONDOWN = 0x0204,
WM_RBUTTONUP = 0x0205,
WM_LBUTTONDBLCLK = 0x0203,
WM_MBUTTONDOWN = 0x0207,
WM_MBUTTONUP = 0x0208
}
[StructLayout(LayoutKind.Sequential)]
public struct POINT
{
public int x;
public int y;
}
[StructLayout(LayoutKind.Sequential)]
public struct MSLLHOOKSTRUCT
{
public POINT pt;
public uint mouseData;
public uint flags;
public uint time;
public IntPtr dwExtraInfo;
}
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetWindowsHookEx(int idHook,
MouseHookHandler lpfn, IntPtr hMod, uint dwThreadId);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool UnhookWindowsHookEx(IntPtr hhk);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr GetModuleHandle(string lpModuleName);
#endregion
}
}
I'm writing an application that binds custom actions to my mouse buttons. For example, I connected the volume up to one of the thumb buttons. Everything works fine as long as I stay in one window because every other windows and the taskbar seems to freeze and it will take some time before the windows are activated again or if I kill my application or the window I am working in.
In the code below I capture the mouse events and check with the settings in the application if the button action is still default or if it has changed. If the action has changed, then the application should for example turn the volume up with two.
[DllImport("kernel32.dll")]
public static extern IntPtr GetModuleHandle(string name);
public delegate int HookProc(int nCode, IntPtr wParam, IntPtr lParam);
public static bool usingKeyboard = false;
public static bool leftButtonDown = false;
static int hMHook;
public const int WH_MOUSE_LL = 14;
//Declare MouseHookProcedure as a HookProc type.
static HookProc MouseHookProcedure;
private enum MouseMessages
{
WM_LBUTTONDOWN = 0x0201,
WM_LBUTTONUP = 0x0202,
WM_MOUSEMOVE = 0x0200,
WM_MOUSEWHEEL = 0x020A,
WM_RBUTTONDOWN = 0x0204,
WM_RBUTTONUP = 0x0205,
WM_XBUTTONDOWN = 0x020B,
WM_XBUTTONUP = 0x020C,
WM_MBUTTONUP = 0x0208,
WM_MBUTTONDOWN = 0x0207
}
[StructLayout(LayoutKind.Sequential)]
public class POINT
{
public int x;
public int y;
}
[StructLayout(LayoutKind.Sequential)]
public class MouseHookStruct
{
public POINT pt;
public int hwnd;
public int wHitTestCode;
public int dwExtraInfo;
}
[DllImport("kernel32.dll")]
static extern uint GetLastError();
[DllImport("user32.dll", CharSet = CharSet.Auto,
CallingConvention = CallingConvention.StdCall)]
public static extern int SetWindowsHookEx(int idHook, HookProc lpfn,
IntPtr hInstance, int threadId);
[DllImport("user32.dll", CharSet = CharSet.Auto,
CallingConvention = CallingConvention.StdCall)]
public static extern bool UnhookWindowsHookEx(int idHook);
[DllImport("user32.dll", CharSet = CharSet.Auto,
CallingConvention = CallingConvention.StdCall)]
public static extern int CallNextHookEx(int idHook, int nCode,
IntPtr wParam, IntPtr lParam);
private int MouseHookProc(int nCode, IntPtr wParam, IntPtr lParam)
{
MouseHookStruct MyMouseHookStruct = (MouseHookStruct)Marshal.PtrToStructure(lParam, typeof(MouseHookStruct));
MouseUsageMessage message = new MouseUsageMessage(1);
MouseUsageManager.mouseUsageMessageQueue.Add(message);
if (nCode >= 0)
{
if (MouseMessages.WM_LBUTTONDOWN == (MouseMessages)wParam)
{
leftButtonDown = true;
} else if (MouseMessages.WM_LBUTTONUP == (MouseMessages)wParam)
{
leftButtonDown = false;
} else if (MouseMessages.WM_RBUTTONDOWN == (MouseMessages)wParam)
{
} else if (MouseMessages.WM_RBUTTONUP == (MouseMessages) wParam) {
} else if (MouseMessages.WM_XBUTTONUP == (MouseMessages)wParam)
{
switch (MyMouseHookStruct.hwnd)
{
case 65536:
if (Settings.Default.thumbClick1User != Settings.Default.thumbClick1Default)
{
ExecuteAction(Settings.Default.thumbClick1User);
return 1;
}
break;
case 131072:
if (Settings.Default.thumbClick2User != Settings.Default.thumbClick2Default)
{
ExecuteAction(Settings.Default.thumbClick2User);
return 1;
}
break;
}
} else if (MouseMessages.WM_MBUTTONDOWN == (MouseMessages)wParam)
{
}
}
return CallNextHookEx(hMHook, nCode, wParam, lParam);
}
Why are the other windows freezing or why can't I use my mouse on the other windows after I've clicked the thumb buttons?
EDIT: Additional code
private void ExecuteAction(string setting)
{
VolumeControl vc = new VolumeControl();
Keybindings kb = new Keybindings();
switch (setting)
{
case "volUp":
vc.VolUp();
break;
case "volDown":
vc.VolDown();
break;
case "cut":
kb.Cut();
break;
case "selectAll":
kb.SelectAll();
break;
case "copy":
kb.Copy();
break;
default:
break;
}
}
The setting string that is sended to the ExecuteAction function is just a string with the action to be performed, i.e. copy, volume up, volume down etc.
VolumeControl class:
public class VolumeControl
{
private const int APPCOMMAND_VOLUME_MUTE = 0x80000;
private const int APPCOMMAND_VOLUME_UP = 0xA0000;
private const int APPCOMMAND_VOLUME_DOWN = 0x90000;
private const int WM_APPCOMMAND = 0x319;
IntPtr handle = Process.GetCurrentProcess().MainWindowHandle;
[DllImport("user32.dll")]
public static extern IntPtr SendMessageW(IntPtr hWnd, int Msg,
IntPtr wParam, IntPtr lParam);
public void VolDown()
{
SendMessageW(handle, WM_APPCOMMAND, handle,
(IntPtr)APPCOMMAND_VOLUME_DOWN);
}
public void VolUp()
{
SendMessageW(handle, WM_APPCOMMAND, handle,
(IntPtr)APPCOMMAND_VOLUME_UP);
}
}
Create Hook function, the function that is called when the class is initialized:
private void createHook()
{
while (hMHook == 0) //|| hKHook == 0)
{
//if (hMHook == 0)
//{
//hMHook = SetWindowsHookEx(WH_MOUSE_LL,
//MouseHookProcedure,
//GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName),
//(IntPtr)0,
//0);
//}
if (hMHook == 0)
{
hMHook = SetWindowsHookEx(WH_MOUSE_LL,
MouseHookProcedure,
GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName),
0);
}
if (hMHook == 0) //|| hKHook == 0)
{
Console.WriteLine("SetWindowsHookEx Failed");
return;
}
Console.WriteLine("Hooked");
}
}
My solution, i have built a simple console project
when you launch program, the hook is activated, and you can toggle with middle mouse button. the right button up and letf button up play with system volume..
the main program:
using HookInput.API;
using HookInput.Mouse;
using System;
using System.Diagnostics;
using System.Windows.Forms;
namespace ConsoleApp3
{
public class Program
{
private static MouseInput mouseInputHook = null;
static void Main(string[] args)
{
var vc = new VolumeControl();
mouseInputHook = new MouseInput(vc);
mouseInputHook.setHook(true);
Console.WriteLine("hook activated");
Application.Run(new ApplicationContext());
}
}
public class VolumeControl
{
private const int APPCOMMAND_VOLUME_MUTE = 0x80000;
private const int APPCOMMAND_VOLUME_UP = 0xA0000;
private const int APPCOMMAND_VOLUME_DOWN = 0x90000;
private const int WM_APPCOMMAND = 0x319;
public IntPtr handle = Process.GetCurrentProcess().MainWindowHandle;
public void VolDown()
{
WindowsHookAPI.SendMessageW(handle, WM_APPCOMMAND, handle, (IntPtr)APPCOMMAND_VOLUME_DOWN);
}
public void VolUp()
{
WindowsHookAPI.SendMessageW(handle, WM_APPCOMMAND, handle, (IntPtr)APPCOMMAND_VOLUME_UP);
}
}
}
the APIs:
using System;
using System.Runtime.InteropServices;
namespace HookInput.API
{
public class WindowsHookAPI
{
//public delegate IntPtr HookDelegate(
// Int32 Code, IntPtr wParam, IntPtr lParam);
public delegate IntPtr HookDelegate(Int32 Code, IntPtr wParam, IntPtr lParam);
[DllImport("User32.dll")]
public static extern IntPtr CallNextHookEx(IntPtr hHook, Int32 nCode, IntPtr wParam, IntPtr lParam);
[DllImport("User32.dll")]
public static extern IntPtr UnhookWindowsHookEx(IntPtr hHook);
[DllImport("User32.dll")]
public static extern IntPtr SetWindowsHookEx(Int32 idHook, HookDelegate lpfn, IntPtr hmod, Int32 dwThreadId);
[DllImport("user32.dll")]
public static extern IntPtr SendMessageW(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam);
}
}
the hook and structures:
using HookInput.API;
using System;
using System.IO.MemoryMappedFiles;
using System.Runtime.InteropServices;
using ConsoleApp3;
namespace HookInput.Mouse
{
public class MouseInput
{
private const Int32 WM_MOUSEMOVE = 0x0200;
private const Int32 WM_LBUTTONDOWN = 0x0201;
private const Int32 WM_LBUTTONUP = 0x0202;
private const Int32 WM_LBUTTONDBLCLK = 0x0203;
private const Int32 WM_RBUTTONDOWN = 0x0204;
private const Int32 WM_RBUTTONUP = 0x0205;
private const Int32 WM_RBUTTONDBLCLK = 0x0206;
private const Int32 WM_MBUTTONDOWN = 0x0207;
private const Int32 WM_MBUTTONUP = 0x0208;
private const Int32 WM_MBUTTONDBLCLK = 0x0209;
private const Int32 WM_MOUSEWHEEL = 0x020A;
private const Int32 WM_XBUTTONDOWN = 0x020B;
private const Int32 WM_XBUTTONUP = 0x020C;
private const Int32 WM_XBUTTONDBLCLK = 0x020D;
private MemoryMappedViewAccessor accessor;
private bool hooked = false;
private WindowsHookAPI.HookDelegate mouseDelegate;
private IntPtr mouseHandle;
private const Int32 WH_MOUSE_LL = 14;
private readonly VolumeControl vc;
public MouseInput(VolumeControl vc)
{
this.vc = vc;
}
public void setHook(bool on)
{
if (hooked == on) return;
if (on)
{
mouseDelegate = MouseHookDelegate;
mouseHandle = WindowsHookAPI.SetWindowsHookEx(WH_MOUSE_LL, mouseDelegate, IntPtr.Zero, 0);
if (mouseHandle != IntPtr.Zero) hooked = true;
}
else
{
WindowsHookAPI.UnhookWindowsHookEx(mouseHandle);
hooked = false;
}
}
private IntPtr MouseHookDelegate(Int32 Code, IntPtr wParam, IntPtr lParam)
{
//mouseData:
//If the message is WM_MOUSEWHEEL, the high-order word of this member is the wheel delta.The low-order word is reserved.
// A positive value indicates that the wheel was rotated forward, away from the user;
// a negative value indicates that the wheel was rotated backward, toward the user.
// One wheel click is defined as WHEEL_DELTA, which is 120.(0x78 or 0xFF88)
//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.
//XBUTTON1 = 0x0001 The first X button was pressed or released.
//XBUTTON2 = 0x0002 The second X button was pressed or released.
MSLLHOOKSTRUCT lparam = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));
int command = (int)wParam;
if (Code < 0 || command == WM_LBUTTONDBLCLK || command == WM_RBUTTONDBLCLK)
return WindowsHookAPI.CallNextHookEx(mouseHandle, Code, wParam, lParam);
else if (command == WM_XBUTTONDOWN || command == WM_XBUTTONUP)
{
int numbutton = ((int)lparam.mouseData >> 16) - 1;
//return (IntPtr)1;
}
else if (command == WM_LBUTTONDOWN || command == WM_LBUTTONUP)
{
if (command == WM_LBUTTONUP)
{
vc.VolDown();
Console.WriteLine("L down");
}
}
else if (command == WM_RBUTTONDOWN || command == WM_RBUTTONUP)
{
if (command == WM_RBUTTONUP)
{
vc.VolUp();
Console.WriteLine("L Up");
}
}
else if (command == WM_MBUTTONDOWN || command == WM_MBUTTONUP)
{
if (hooked)
{
setHook(false);
Console.WriteLine("hook deactivated");
}
else
{
setHook(true);
Console.WriteLine("hook activated");
}
}
else if (command == WM_MOUSEWHEEL)
{
}
return WindowsHookAPI.CallNextHookEx(mouseHandle, Code, wParam, lParam);
}
~MouseInput()
{
}
[StructLayout(LayoutKind.Sequential)]
private struct POINT
{
public int x;
public int y;
}
[StructLayout(LayoutKind.Sequential)]
private struct MSLLHOOKSTRUCT
{
public POINT pt;
public uint mouseData;
public uint flags;
public uint time;
public IntPtr dwExtraInfo;
}
}
}
After few minutes of successfull running I get this error in my application.
A callback was made on a garbage collected delegate of type
'myApp!myApp.globalKeyboardHook+keyboardHookProc::Invoke'.
I know this is because the garbage collector has killed an object or something else and my code is still referring the same thing.
If that is the case which object or component is more likely to be collected by the GC. How can I overcome this error. (having a ref ??)
Since I cant figure out which part of the code is in responsible for this issue, I'm posting the complete class here. (I guess it has no issue with my other classes)
class globalKeyboardHook
{
public delegate int keyboardHookProc(int code, int wParam, ref keyboardHookStruct lParam);
public struct keyboardHookStruct
{
public int vkCode;
public int scanCode;
public int flags;
public int time;
public int dwExtraInfo;
}
IntPtr hInstance;
const int WH_KEYBOARD_LL = 13;
const int WM_KEYDOWN = 0x100;
const int WM_SYSKEYDOWN = 0x104;
public List<Keys> HookedKeys = new List<Keys>();
IntPtr hhook = IntPtr.Zero;
// Events
public event KeyEventHandler KeyDown;
public globalKeyboardHook()
{
hook();
}
~globalKeyboardHook()
{
unhook();
}
public void hook()
{
hInstance = LoadLibrary("User32");
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);
}
public void unhook()
{
UnhookWindowsHookEx(hhook);
}
public int hookProc(int code, int wParam, ref keyboardHookStruct lParam)
{
if (code >= 0)
{
Keys key = (Keys)lParam.vkCode;
if (1 == 1)
{
KeyEventArgs kea = new KeyEventArgs(key);
if ((wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN) && (KeyDown != null))
{
KeyDown(this, kea);
}
if (kea.Handled)
return 1;
}
}
return CallNextHookEx(hhook, code, wParam, ref lParam);
}
// DLL imports
[DllImport("user32.dll")]
static extern IntPtr SetWindowsHookEx(int idHook, keyboardHookProc callback, IntPtr hInstance, uint threadId);
[DllImport("user32.dll")]
static extern bool UnhookWindowsHookEx(IntPtr hInstance);
[DllImport("user32.dll")]
static extern int CallNextHookEx(IntPtr idHook, int nCode, int wParam, ref keyboardHookStruct lParam);
[DllImport("kernel32.dll")]
static extern IntPtr LoadLibrary(string lpFileName);
}
}
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);
You'll certainly have trouble finding the collected item, it is not visible in your program. The C# language is a bit too friendly here. You are relying on its syntax sugar to automagically create a delegate object for hookProc. This code is compiled to:
keyboardHookProc $unspeakable = new keyboardHookProc(hookProc);
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, $unspeakable, hInstance, 0);
Which is a problem in pinvoke, the garbage collector has no idea that the $unspeakable delegate object is actually being used by native code. It can only see managed references to objects. So it collects the object as soon as a gen #0 garbage collection occurs. Kaboom when Windows makes the hook callback.
It is up to you to ensure that this delegate object cannot be collected. Use GCHandle.Alloc(). Or the simple way, storing it in a variable explicitly. Which is fine here since you let the finalizer destroy the hook:
IntPtr hhook = IntPtr.Zero;
keyboardHookProc callback;
public void hook()
{
if (callback != null) throw new InvalidOperationException("Hook already installed");
if (hInstance == IntPtr.Zero) hInstance = LoadLibrary("User32");
callback = new keyboardHookProc(hookProc);
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, callback, hInstance, 0);
}
public void unhook()
{
UnhookWindowsHookEx(hhook);
callback = null;
}
I am using the code below but with little modification:
class globalKeyboardHook {
public struct keyboardHookStruct {
public int vkCode;
public int scanCode;
public int flags;
public int time;
public int dwExtraInfo;
}
public delegate int keyboardHookProc(int code, int wParam, ref keyboardHookStruct lParam);
public keyboardHookProc hookP;
const int WH_KEYBOARD_LL = 13;
const int WM_KEYDOWN = 0x100;
const int WM_KEYUP = 0x101;
const int WM_SYSKEYDOWN = 0x104;
const int WM_SYSKEYUP = 0x105;
#endregion
public List<Keys> HookedKeys = new List<Keys>();
IntPtr hhook = IntPtr.Zero;
public event KeyEventHandler KeyDown;
public event KeyEventHandler KeyUp;
public globalKeyboardHook() {
hook();
}
~globalKeyboardHook() {
unhook();
}
public void hook() {
IntPtr hInstance = LoadLibrary("User32");
hookP = new keyboardHookProc(hookProc);
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookP, hInstance, 0);
}
public void unhook() {
UnhookWindowsHookEx(hhook);
}
public int hookProc(int code, int wParam, ref keyboardHookStruct lParam) {
if (code >= 0) {
Keys key = (Keys)lParam.vkCode;
if (HookedKeys.Contains(key)) {
KeyEventArgs kea = new KeyEventArgs(key);
if ((wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN) && (KeyDown != null)) {
KeyDown(this, kea) ;
} else if ((wParam == WM_KEYUP || wParam == WM_SYSKEYUP) && (KeyUp != null)) {
KeyUp(this, kea);
}
if (kea.Handled)
return 1;
}
}
return CallNextHookEx(hhook, code, wParam, ref lParam);
}
[DllImport("user32.dll")]
static extern IntPtr SetWindowsHookEx(int idHook, keyboardHookProc callback, IntPtr hInstance, uint threadId);
[DllImport("user32.dll")]
static extern bool UnhookWindowsHookEx(IntPtr hInstance);
[DllImport("user32.dll")]
static extern int CallNextHookEx(IntPtr idHook, int nCode, int wParam, ref keyboardHookStruct lParam);
[DllImport("kernel32.dll")]
static extern IntPtr LoadLibrary(string lpFileName);
}
Sometimes after a few keypresses "hookProc" doesnt get called, as if i have "unhooked" the event, and it wont capture any keystrokes at all. How can i make sure that it never unhooks the event unless i do it in manually? How can i ensure that i keep subscribing to the hook?
Thank you.
It logs the keys to textbox currently so its safe.
PROBLEM
The problem is when i run this at virtual machine, or my friends laptop,
it hangs after pressing certain amount of keys(random).It runs perfectly fine in mine.
http://i34.tinypic.com/29o1im8.jpg
class GlobalKeyboardHook
{
#region Definition of Structures, Constants and Delegates
public delegate int KeyboardHookProc(int nCode, int wParam, ref GlobalKeyboardHookStruct lParam);
public struct GlobalKeyboardHookStruct
{
public int vkCode;
public int scanCode;
public int flags;
public int time;
public int dwExtraInfo;
}
const int WM_KEYDOWN = 0x100;
const int WM_KEYUP = 0x101;
const int WM_SYSKEYDOWN = 0x104;
const int WM_SYSKEYUP = 0x105;
const int WH_KEYBOARD_LL = 13;
#endregion
#region Events
public event KeyEventHandler KeyDown;
public event KeyEventHandler KeyUp;
#endregion
#region Instance Variables
public List<Keys> HookedKeys = new List<Keys>();
IntPtr hookHandle = IntPtr.Zero;
#endregion
#region DLL Imports
[DllImport("kernel32.dll")]
static extern IntPtr LoadLibrary(string lpFileName);
[DllImport("user32.dll", CharSet = CharSet.Auto,CallingConvention = CallingConvention.StdCall, SetLastError = true)]
static extern IntPtr SetWindowsHookEx(int hookID, KeyboardHookProc callback, IntPtr hInstance, uint threadID);
[DllImport("user32.dll", CharSet = CharSet.Auto,CallingConvention = CallingConvention.StdCall, SetLastError = true)]
static extern bool UnhookWindowsHookEx(IntPtr hookHandle);
[DllImport("user32.dll", CharSet = CharSet.Auto,CallingConvention = CallingConvention.StdCall)]
static extern int CallNextHookEx(IntPtr hookHandle, int nCode, int wParam, ref GlobalKeyboardHookStruct lParam);
#endregion
#region Public Methods
public int hookProc(int nCode, int wParam, ref GlobalKeyboardHookStruct lParam)
{
if (nCode >= 0)
{
Keys key = (Keys)lParam.vkCode;
if (HookedKeys.Contains(key) == true)
{
KeyEventArgs kea = new KeyEventArgs(key);
if ((wParam == WM_KEYUP || wParam == WM_SYSKEYUP) && KeyUp != null)
{
KeyUp(this, kea);
}
else if ((wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN) && KeyDown != null)
{
KeyDown(this, kea);
}
if (kea.Handled) return 1;
}
}
return CallNextHookEx(hookHandle, nCode, wParam, ref lParam);
}
public void hook()
{
IntPtr hInstance = LoadLibrary("user32");
hookHandle = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);
}
public void unhook()
{
UnhookWindowsHookEx(hookHandle);
}
#endregion
#region Constructors and Destructors
public GlobalKeyboardHook()
{
hook();
}
~GlobalKeyboardHook()
{
unhook();
}
#endregion
Try debugging your application with the "CallbackOnCollectedDelegate" MDA turned on (Debug -> Exceptions -> Managed Debugging Assistants -> check "CallbackOnCollectedDelegate").
The common bug here is that the delegate for your hook procedure is automatically collected by the GC after you set the hook (it gets created as part of the P/Invoke marshaling to SetWindowsHookEx). After the GC collects the delegate, the program crashes when trying to call the callback. This would also explain the randomness.
If this is your issue, you'll see an error like the following:
A callback was made on a garbage
collected delegate of type '...'.
This may cause application crashes,
corruption and data loss. When passing
delegates to unmanaged code, they must
be kept alive by the managed
application until it is guaranteed
that they will never be called.
Try keeping a reference to your hook procedure as a member in your class, e.g.:
public delegate int KeyboardHookProc(int nCode, int wParam, ref GlobalKeyboardHookStruct lParam);
public int hookProc(int nCode, int wParam, ref GlobalKeyboardHookStruct lParam)
{
// ...
}
public void hook()
{
_hookProc = new KeyboardHookProc(hookProc);
IntPtr hInstance = LoadLibrary("user32");
hookHandle = SetWindowsHookEx(WH_KEYBOARD_LL, _hookProc, hInstance, 0);
}
KeyboardHookProc _hookProc;