Re: QASetWindowsJournalHook by managed code

I feel sorry but the truth is I don't understand what's wrong with my GCHandles.

ex:
public static GCHandle gc2 = GCHandle.Alloc(MouseHookProcedure, GCHandleType.Pinned);

then the MouseHookProcedure already be pinned, isn't ?
I found many examples they just use by this way.

Please let me know if I am wrong here, maybe I missed something but I really can't find it.

Regarding pass the HookProc
1. I choose pinned type not just normal type.
2. I tried pass MouseHookProcedure directly, fail.
3. then I tried to pass address of gc2, same, fail
4. OK, I tried GetFunctionPointerForDelegate then pass this pointer, OK, still fail.

by the way, I also compared the working unmanaged code so many times, I still can't see the problem.

Unmanged code here is simple, set and pass. nothing special then see working so great, that's why I so frustraed here... please can you help, appreciate.

P.S I am newbie to managed code and CF, I even don't know how to check memroy ...

"Chris Tacke, eMVP" <ctacke.at.opennetcf.dot.com> wrote in message news:e0BHzKitJHA.1212@xxxxxxxxxxxxxxxxxxxxxxx
Again, WTF are you using all of these GCHandles for? The fact you keep throwing them (and more and more it seems) indicates that you clearly don't understand them. To improve your development skills, you need to *understand* the code you write. You need to understand that an IntPtr and int and a GCHandle are all actually very closely related items (and in fact so is a delegate). They are all simply 32-bit integers. Managed code gives them different significance, and how the GC treats them varies slightly, but it's really all syntactic sugar around a very, very basic and fundamental thing.

Let me be clear - I'm not going to just write and test this code for you. I don't have the time or the inclination - I already work long days and the only reason I do stuff that isn't related to something I need to be doing is if I find it interesting. I did hooking a long time ago and got it working, so it no longer really interests me.

The confusion you're having is one of the main reasons I think that to be a good managed developer you still *must* understand C. You need to understand, and understand well, how memory works. This is an excellent opportunity for you to actually learn what is happening and why what you have is failing. A good step would be to write what you want to happen in native code and get that working. The translate what you have in native code to managed code. I still do this exercise a lot when writing managed calls to native stuff, especially if it's complex, so I can use the Memory View and see if the addresses getting passed around make sense in both managed and native. If you're not doing that, then you need to learn how or this kind of problem will always be a black box to you and your development skills will never progress beyond mediocre.


--

Chris Tacke, Embedded MVP
OpenNETCF Consulting
Giving back to the embedded community
http://community.OpenNETCF.com



"Jack P" <private@xxxxxxxxxxxx> wrote in message news:uXnRaWhtJHA.5376@xxxxxxxxxxxxxxxxxxxxxxx
I feel so frustrated, it just can't work.
and
I compared your code, I only found the differences below:

1. QASetWindowsJournalHook return IntPtr, my is return Int.
2. JournalHookStruct , my is a class.
3. delegate int HookProc, my is public

I don't think they are problems, however, I still tried everything became the same as yours, but still can't work ( will crash after executed any other program )

Here is my latest code, could you help to review ? appreciate.

//////////////////////////////////////////////////////////////////////
using System;
using System.Linq;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace JB
{

public partial class Form1 : Form
{
public struct JournalHookStruct
{
public int message;
public int paramL;
public int paramH;
public int time;
public IntPtr hwnd;
}

public static IntPtr hHook;
public static IntPtr GwParam; // for MouseHookProc
public static IntPtr GlParam; // for MouseHookProc
public delegate int HookProc(int nCode, IntPtr wParam, IntPtr lParam);
public static JournalHookStruct myHookMessage = new JournalHookStruct();
public static HookProc MouseHookProcedure = new HookProc(MouseHookProc);
public static IntPtr pMouseHookProcedure = Marshal.GetFunctionPointerForDelegate(MouseHookProcedure);

/// <summary>
/// try to keep everything alive
/// </summary>
public static GCHandle gc1 = GCHandle.Alloc(myHookMessage, GCHandleType.Pinned);
public static GCHandle gc2 = GCHandle.Alloc(MouseHookProcedure, GCHandleType.Pinned);
public static GCHandle gc3 = GCHandle.Alloc(pMouseHookProcedure, GCHandleType.Pinned);
public static GCHandle gc4 = GCHandle.Alloc(hHook, GCHandleType.Pinned);
public static GCHandle gc5 = GCHandle.Alloc(GwParam, GCHandleType.Pinned);
public static GCHandle gc6 = GCHandle.Alloc(GlParam, GCHandleType.Pinned);

public static int MouseHookProc(int nCode, IntPtr wParam, IntPtr lParam)
{
while (false)
{
int a = 1;
}
GwParam = wParam;
GlParam = lParam;
return NativeDLLs.CallNextHookEx(gc4.AddrOfPinnedObject(), nCode, gc5.AddrOfPinnedObject(), gc6.AddrOfPinnedObject()); // pass wParam / lParam directly, the result is the same.
}

public Form1()
{
InitializeComponent();
hHook = NativeDLLs.QASetWindowsJournalHook(0, pMouseHookProcedure, gc1.AddrOfPinnedObject()); // whatever pass MouseHookProcedure , address of gc2, target of gc3, result are the same => will crash after executed other program
}
}

public class NativeDLLs
{
public enum HookType
{
JournalRecord = 0,
JournalPlayback = 1,
KeyboardLowLevel = 20
}

[DllImport("coredll.dll", SetLastError = true)]
public static extern IntPtr GetModuleHandle(string mod);

[DllImport("coredll.dll", SetLastError = true)]
public static extern IntPtr QASetWindowsJournalHook(HookType nFilterType, IntPtr pfnFilterProc, IntPtr pfnEventMsg);

[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("CoreDll.dll", EntryPoint = "QAUnhookWindowsJournalHook", SetLastError = true)]
public static extern int QAUnhookWindowsJournalHook(IntPtr hook);

[DllImport("CoreDll.dll", CharSet = CharSet.Auto/*,CallingConvention = CallingConvention.StdCall)*/)]
public static extern int CallNextHookEx(IntPtr idHook, int nCode, IntPtr wParam, IntPtr lParam);
}

}




"Chris Tacke, eMVP" <ctacke.at.opennetcf.dot.com> wrote in message news:etAMs1XtJHA.3816@xxxxxxxxxxxxxxxxxxxxxxx
Just digging though code I have, I see this:

#if !DESKTOP
[DllImport("coredll.dll", SetLastError = true)]
public static extern IntPtr GetModuleHandle(string mod);

[DllImport("coredll.dll", SetLastError = true)]
public static extern IntPtr QASetWindowsJournalHook(HookType nFilterType, HookProc pfnFilterProc, ref JournalHookStruct pfnEventMsg);

/*
HHOOK
WINAPI
QASetWindowsJournalHook(
int nFilterType,
HOOKPROC pfnFilterProc,
EVENTMSG *pfnEventMsg
);
*/
#endif


/*
* From pwinuser.h
*
typedef struct tagEVENTMSG {
UINT message;
UINT paramL;
UINT paramH;
DWORD time;
HWND hwnd;
} EVENTMSG, *PEVENTMSGMSG, NEAR *NPEVENTMSGMSG, FAR *LPEVENTMSGMSG;
*/
public struct JournalHookStruct
{
public int message;
public int paramL;
public int paramH;
public int time;
public IntPtr hwnd;
}

/*
* From pwinuser.h
*
#define WH_JOURNALRECORD 0
#define WH_JOURNALPLAYBACK 1
#define WH_KEYBOARD_LL 20
*/
internal enum HookType
{
JournalRecord = 0,
JournalPlayback = 1,
KeyboardLowLevel = 20
}

internal delegate int HookProc(HookCode nCode, IntPtr wParam, IntPtr lParam);


That should get you a long ways there.


--

Chris Tacke, Embedded MVP
OpenNETCF Consulting
Giving back to the embedded community
http://community.OpenNETCF.com

"Jack P" <private@xxxxxxxxxxxx> wrote in message news:OZ86VzVtJHA.1088@xxxxxxxxxxxxxxxxxxxxxxx
could you teach me where is wrong ?

I almost try everything out .....





"Chris Tacke, eMVP" <ctacke.at.opennetcf.dot.com> wrote in message news:un7lxxStJHA.4364@xxxxxxxxxxxxxxxxxxxxxxx
Now it looks like you're just throwing code at the wall hoping something will stick. You need to go back and reasearch what a GCHandle is and understand when you should and shouldn't use them. You seem to just have them in here to have them. You also need to see how GetFunctionPointerForDelegate works and exactly what it returns. You need to *understand* the code, not just grasp at straws.


--

Chris Tacke, Embedded MVP
OpenNETCF Consulting
Giving back to the embedded community
http://community.OpenNETCF.com


"Jack P" <private@xxxxxxxxxxxx> wrote in message news:O%23xELRLtJHA.1236@xxxxxxxxxxxxxxxxxxxxxxx
Hi Chris,
I added few lines as following for GetFunctionPointerForDelegate:

public static IntPtr pMouseHookProcedure = Marshal.GetFunctionPointerForDelegate(MouseHookProcedure);
public static GCHandle gc3 = GCHandle.Alloc(pMouseHookProcedure, GCHandleType.Pinned);

and changed the init_hook() as following:
public static void init_hook() /////////////////// change (HookProc) to (IntPtr) because can't convert IntPtr back to HookProc) //////
{
hHook = LibWrap.QASetWindowsJournalHook(0, pMouseHookProcedure, gc1.AddrOfPinnedObject());
}

It didn't work yet ( behave the same as before, system will crash after execute other program )
and here is my complete code:
/////////////////////////////////////////////////////////////////
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Security.Permissions;

namespace ClassLibrary1
{
unsafe public delegate int HookProc(int nCode, IntPtr wParam, IntPtr lParam);
[SecurityPermission(SecurityAction.Demand, UnmanagedCode = true)]
unsafe public class Class1
{
private const int WM_LBUTTONDBLCLK = 515;
private const int WH_JOURNALRECORD = 0;
public static int hHook = 0;
unsafe public static EVENTMSG myHookMessage = new EVENTMSG();
unsafe public static HookProc MouseHookProcedure = MouseHookProc;
public static IntPtr pMouseHookProcedure = Marshal.GetFunctionPointerForDelegate(MouseHookProcedure);

public static int MouseHookProc(int nCode, IntPtr wParam, IntPtr lParam)
{
return LibWrap.CallNextHookEx(hHook, nCode, wParam, lParam);
}

public static GCHandle gc1 = GCHandle.Alloc(myHookMessage, GCHandleType.Pinned);
public static GCHandle gc2 = GCHandle.Alloc(MouseHookProcedure, GCHandleType.Pinned);
public static GCHandle gc3 = GCHandle.Alloc(pMouseHookProcedure, GCHandleType.Pinned);

public static void init_hook()
{
hHook = LibWrap.QASetWindowsJournalHook(0, pMouseHookProcedure, gc1.AddrOfPinnedObject());
}
}

public class LibWrap
{
[DllImport("CoreDll.dll", SetLastError = true)]
//public static extern int QASetWindowsJournalHook(int nFilterType, HookProc pfnFilterProc, ref EVENTMSG pfnEventMsg);
public static extern int QASetWindowsJournalHook(int nFilterType, IntPtr pfnFilterProc, IntPtr pfnEventMsg);
[DllImport("CoreDll.dll", EntryPoint = "QAUnhookWindowsJournalHook", SetLastError = true)]
internal static extern int QAUnhookWindowsJournalHook(int hook);
[DllImport("CoreDll.dll", CharSet = CharSet.Auto/*,CallingConvention = CallingConvention.StdCall)*/)]
public static extern int CallNextHookEx(int idHook, int nCode, IntPtr wParam, IntPtr lParam);
}
[StructLayout(LayoutKind.Sequential)]
public class EVENTMSG
{
public int message;
public Int16 x;
public Int16 y;

public int paramH;
public int time;
public int hwnd;
}
}


Appreciate,
JB.

"Chris Tacke, eMVP" <ctacke.at.opennetcf.dot.com> wrote in message news:efslHVKtJHA.5836@xxxxxxxxxxxxxxxxxxxxxxx
You are still using these things *way* wrong. My guess (without putting too much grey matter into it) is that you need to create a delegate and call GetFunctionPointForDelegate and pass that. You also shouldn't be passing the Target of the GCHandle anywhere.

-Chris


"Jack P" <private@xxxxxxxxxxxx> wrote in message news:%23Yup05JtJHA.4452@xxxxxxxxxxxxxxxxxxxxxxx
I found something wrong in my application, in fact it didn't really work, why I didn't see crash that is because the callback didn't assign correctly when using GCHandle.
I list my complete code as following, it packaged as C# DLL, it will crash after perform any other program. ( if not exit this program, everything looks fine )

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Security.Permissions;

namespace ClassLibrary1
{
unsafe public delegate int HookProc(int nCode, IntPtr wParam, IntPtr lParam);
[SecurityPermission(SecurityAction.Demand, UnmanagedCode = true)]
unsafe public class Class1
{
private const int WM_LBUTTONDBLCLK = 515;
private const int WH_JOURNALRECORD = 0;
public static int hHook = 0;
unsafe public static EVENTMSG myHookMessage = new EVENTMSG();
unsafe public static HookProc MouseHookProcedure = MouseHookProc;

unsafe public static GCHandle gc1 = GCHandle.Alloc(myHookMessage, GCHandleType.Pinned);
unsafe public static GCHandle gc2 = GCHandle.Alloc(MouseHookProcedure, GCHandleType.Pinned);

unsafe public static int MouseHookProc(int nCode, IntPtr wParam, IntPtr lParam) ////////////////// HERE is the hookproc /////////////
{
return LibWrap.CallNextHookEx(hHook, nCode, wParam, lParam);
}

public static void init_hook() ////////////////// HERE is the init /////////////
{
hHook = LibWrap.QASetWindowsJournalHook(0,(HookProc) gc2.Target, gc1.AddrOfPinnedObject());
}
}

public class LibWrap ////////// class for DLL /////////
{
[DllImport("CoreDll.dll", SetLastError = true)]
//public static extern int QASetWindowsJournalHook(int nFilterType, HookProc pfnFilterProc, ref EVENTMSG pfnEventMsg);
public static extern int QASetWindowsJournalHook(int nFilterType, HookProc pfnFilterProc, IntPtr pfnEventMsg);
[DllImport("CoreDll.dll", EntryPoint = "QAUnhookWindowsJournalHook", SetLastError = true)]
internal static extern int QAUnhookWindowsJournalHook(int hook);
[DllImport("CoreDll.dll", CharSet = CharSet.Auto/*,CallingConvention = CallingConvention.StdCall)*/)]
public static extern int CallNextHookEx(int idHook, int nCode, IntPtr wParam, IntPtr lParam);
}
[StructLayout(LayoutKind.Sequential)]
public class EVENTMSG
{
public int message;
public Int16 x;
public Int16 y;

public int paramH;
public int time;
public int hwnd;
}
}

Appreciate for your help.
JB.


"Jack P" <private@xxxxxxxxxxxx> wrote in message news:OkQLro8sJHA.1492@xxxxxxxxxxxxxxxxxxxxxxx
OK, I have to say I am newbie to handle something : D

Everything great now :D

Appreciate! Chris!

"Chris Tacke, eMVP" <ctacke.at.opennetcf.dot.com> wrote in message news:eHVExH7sJHA.4648@xxxxxxxxxxxxxxxxxxxxxxx
1. I don't see your definition of the P/Invoke.
2. What are the GCHandles for? You're never using them.
3. I'm surprised it works as well as it does. My *guess* at this point is that you got lucky and the actual callback function address got passed in to the hook procedure (I wouldn't have guessed it), but the address is the slot 0 address. When you change programs, your app is no longer in slot 0, the running app is, and so that slot 0 address now points to something altogether different, and when the hook tries to call it it pukes.

I know these work as I've done them.

--

Chris Tacke, Embedded MVP
OpenNETCF Consulting
Giving back to the embedded community
http://community.OpenNETCF.com

"Jack P" <private@xxxxxxxxxxxx> wrote in message news:uH1pRA6sJHA.3928@xxxxxxxxxxxxxxxxxxxxxxx
Hi Chris,
Thanks for help, I changed code as follows but result is the same, regarding the leakage, I guess you mean the GCHandle never free in code, I guess it will OK because enough memory for leakage ... just to make sure everything should exist in memory all the time ....

public class Class1
{
public static int hHook = 0;
public static EVENTMSG myHookMessage = new EVENTMSG();
public static GCHandle gc1 = GCHandle.Alloc(myHookMessage, GCHandleType.Pinned);
public static GCHandle gc2 = GCHandle.Alloc(MouseHookProcedure, GCHandleType.Pinned);
public static GCHandle gc3 = GCHandle.Alloc(hHook, GCHandleType.Pinned);
...
public static void init_hook()
{
myHookMessage.hwnd = 0; ;
myHookMessage.message = 0;
myHookMessage.paramH = 0;
myHookMessage.time = 0;
hHook = QASetWindowsJournalHook(0, MouseHookProcedure, ref myHookMessage);
}

The Class1 was packaged to DLL then called from my application, I am not sure it will help or not.
or I should package Native C DLL to make sure no memory collection ?

I still can't get my application work .... please help, appreciate!

J.B.

"Chris Tacke, eMVP" <ctacke.at.opennetcf.dot.com> wrote in message news:eHeyiv4sJHA.4684@xxxxxxxxxxxxxxxxxxxxxxx
My guess is that the gchandle is going out of scope and getting collected. If not you still have a memory leak.


--

Chris Tacke, Embedded MVP
OpenNETCF Consulting
Giving back to the embedded community
http://community.OpenNETCF.com

"Jack P" <private@xxxxxxxxxxxx> wrote in message news:%239cbS40sJHA.4632@xxxxxxxxxxxxxxxxxxxxxxx
Hi All,

I am trying QASetWindowsJournalHook() in c#, it works but having some problem.

I can receive the hooked message correctly ( mouse move, click, x , y ...etc ), but as long as I do something as below, the system (ppc) will crash.

1. Run my c# QASetWindowsJournalHook application, working.
2. Click [Start], my application is still working, message received well.
3. Click [Today] or [Setup] or [IE] ... whatever the next program is .... the while system will crash ( stop there then can't do anything .... )

public static int MouseHookProc(int nCode, IntPtr wParam, IntPtr lParam)
{
return CallNextHookEx(hHook, nCode, wParam, lParam);
}

I also tried to GCHandle everything but result is the same ...

public static void init_hook()
{
EVENTMSG myHookMessage = new EVENTMSG();
myHookMessage.message = 0;
myHookMessage.paramH = 0;
myHookMessage.time = 0;

GCHandle gc1 = GCHandle.Alloc(myHookMessage, GCHandleType.Pinned);
GCHandle gc2 = GCHandle.Alloc(MouseHookProcedure, GCHandleType.Pinned);
GCHandle gc3 = GCHandle.Alloc(hHook, GCHandleType.Pinned);

hHook = QASetWindowsJournalHook(0, MouseHookProcedure, ref myHookMessage);
}

and I also tried to package the hook functions into a c# DLL ...

but result is the same ... will also crash ...

Can somebody help ?

Appreciate!
JB
















.