Re: Hook on right button mouse - C# Discussion Boards

7-May-09 6:52

Hello;
I'm building an application in winforms c# 3.0. I want to disable the mouses's right button click when the application is running on all the system (in order to prevent copy/paste).
I succeeded in blocking the keyboard keys but not the mouse button. Can you figure out why the code for the mouse does not work?
The problem comes from LowLevelMouseProc()
Thanks for help.

#region
 
using System;
using System.ComponentModel;
using System.Drawing;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Windows.Forms;
 
#endregion
 
namespace GlobalHook
{
    public class UserActivityHook
    {
        private const int VmRButton = 0x02;
        private const int VkLControl = 0xA2;
        private const int VkRControl = 0xA3;
        private const int VkControl = 0x11;
        private const int VkSnapshot = 0x2C;
        private const int WhKeyboardLl = 13;
        private const int WhMouseLl = 14;
        private const int WmKeydown = 0x0100;
        private const int WmMousedown =0x0201;
        private static IntPtr kbh_Handle;
        private static IntPtr kbh_Handle1;
 
        private static HookProc KeyboardHookProcedure;
        private static HookProc MouseHookProcedure;     
        private int HMouseHook;        
        private int HKeyboardHook;
 
        #region Windows Function Imports
 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall,
            SetLastError = true)]
        private static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hMod, int dwThreadId);
 
 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall,
            SetLastError = true)]
        public static extern int CallNextHookEx(IntPtr hhk, int nCode, int wParam, IntPtr lParam);
 
 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall,
            SetLastError = true)]
        private static extern int UnhookWindowsHookEx(int idHook);
 
 
        private delegate int HookProc(int nCode, int wParam, IntPtr lParam);
 
        #endregion
 
        #region Windows constants
 
        #endregion
 
        ~UserActivityHook()
        {
            //uninstall hooks and do not throw exceptions
            Stop(true, true, false);
           
        }
 
        public void Start()
        {
 
            if (HMouseHook == 0)
            {
                // Create an instance of HookProc.
                MouseHookProcedure = new HookProc(LowLevelMouseProc);
                //install hook
                HMouseHook = SetWindowsHookEx(WhMouseLl, MouseHookProcedure, Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);
                //If SetWindowsHookEx fails.
                if (HMouseHook== 0)
                {
                    //Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set. 
                    int errorCode = Marshal.GetLastWin32Error();
                    //do cleanup
                    Stop(true, false, false);
                    //Initializes and throws a new instance of the Win32Exception class with the specified error. 
                    throw new Win32Exception(errorCode);
                }
            }
 
 
 
            // install Keyboard hook only if it is not installed and must be installed
            if (HKeyboardHook == 0)
            {
                // Create an instance of HookProc.
                KeyboardHookProcedure = new HookProc(LowLevelKeyboardProc);
                //install hook
                HKeyboardHook = SetWindowsHookEx(WhKeyboardLl, KeyboardHookProcedure,
                                                 Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),
                                                 0);
                //If SetWindowsHookEx fails.
                if (HKeyboardHook == 0)
                {
                    //Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set. 
                    int errorCode = Marshal.GetLastWin32Error();
                    //do cleanup
                    Stop(false, true, false);
                    //Initializes and throws a new instance of the Win32Exception class with the specified error. 
                    throw new Win32Exception(errorCode);
                }
            }
        }
 
        public void Stop()
        {
            Stop(true, true, true);
        }
 
 
        public void Stop(bool uninstallMouseHook, bool uninstallKeyboardHook, bool throwExceptions)
        {
            if (HMouseHook != 0 && uninstallMouseHook)
            {
                //uninstall hook
                int retMouse = UnhookWindowsHookEx(HMouseHook);
                //reset invalid handle
                HMouseHook = 0;
                //if failed and exception must be thrown
                if (retMouse == 0 && throwExceptions)
                {
                    //Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set. 
                    int errorCode = Marshal.GetLastWin32Error();
                    //Initializes and throws a new instance of the Win32Exception class with the specified error. 
                    throw new Win32Exception(errorCode);
                }
            }
 
            //if keyboard hook set and must be uninstalled
            if (HKeyboardHook != 0 && uninstallKeyboardHook)
            {
                //uninstall hook
                int retKeyboard = UnhookWindowsHookEx(HKeyboardHook);
                //reset invalid handle
                HKeyboardHook = 0;
                //if failed and exception must be thrown
                if (retKeyboard == 0 && throwExceptions)
                {
                    //Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set. 
                    int errorCode = Marshal.GetLastWin32Error();
                    //Initializes and throws a new instance of the Win32Exception class with the specified error. 
                    throw new Win32Exception(errorCode);
                }
            }
        }
 
 
     
 
        private static int LowLevelKeyboardProc(int nCode, int wParam, IntPtr lParam)
        {
            if (nCode < 0)
            {
                CallNextHookEx(kbh_Handle, nCode, wParam, lParam);
                return 0;
            }
 
            if (wParam == WmKeydown)
            {
                IntPtr kbdll = lParam;
                Kbdllhookstruct kbdllstruct = (Kbdllhookstruct) Marshal.PtrToStructure(kbdll, typeof (Kbdllhookstruct));
 
                if ((kbdllstruct.VkCode == VkSnapshot) || (kbdllstruct.VkCode == VkControl) || (kbdllstruct.VkCode == VkLControl) || (kbdllstruct.VkCode == VkRControl))
                    return -1;
            }
 
            return CallNextHookEx(kbh_Handle, nCode, wParam, lParam);
        }
 
 
 
 
        private static int LowLevelMouseProc(int nCode, int wParam, IntPtr lParam)
        {
            if (nCode < 0)
            {
                CallNextHookEx(kbh_Handle1, nCode, wParam, lParam);
                return 0;
            }
 
            if (wParam == WmMousedown)
            {
                IntPtr msdll = lParam;
                MouseLlHookStruct msdllstruct = (MouseLlHookStruct)Marshal.PtrToStructure(msdll, typeof(MouseLlHookStruct));
 
                if (msdllstruct.MouseData == VmRButton)
                    return -1;
            }
 
            return CallNextHookEx(kbh_Handle1, nCode, wParam, lParam);
        }
 
 
        [StructLayout(LayoutKind.Sequential)]
        private struct Point
        {
            public int X;
            public int Y;
        }
 
 
 
        [StructLayout(LayoutKind.Sequential)]
        private struct MouseLlHookStruct
        {
            public Point Point;
            public int MouseData;
            public int Flags;
            public int Time;
            public int ExtraInfo;
        }
    
 
        #region Nested type: Kbdllhookstruct
 
        [StructLayout(LayoutKind.Sequential)]
        public struct Kbdllhookstruct
        {
            public int VkCode;
            public int ScanCode;
            public int Flags;
            public int Time;
            public int ExtraInfo;
        }
 
        #endregion
    }
}

Dave Kreskowiak7-May-09 7:24

Dave Kreskowiak

7-May-09 7:24

teycir wrote:
(in order to prevent copy/paste).

This is a lot of work just to find out your premise is flawed. You are not going to prevent all possible Copy'N'Paste possibilities just by hooking the mouse and eating the right button clicks. Besides, applications use the right button for other things other than Copy'N'Paste.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

harold aptroot7-May-09 7:42

harold aptroot

7-May-09 7:42

teycir wrote:
in order to prevent copy/paste

So you're writing a piece of malware and asking for help.
Is there a good reason to prevent copy/paste? I don't think so.
Disabling the right mouse button is not going to help though.

Dan Neely7-May-09 9:31

Dan Neely

7-May-09 9:31

Why are you trying to disable copy/paste systemwide? I can't think of a single legit reason to do so. If your requirement is to keep the user from copying data out of your application, your focus should be on changing the behavior of your application only; not affecting the entire system.

It is a truth universally acknowledged that a zombie in possession of brains must be in want of more brains.
-- Pride and Prejudice and Zombies

Member 10339077-May-09 12:57

7-May-09 12:57

Others are right, forget this line of reasoning. As an example of another approach - you can monitor the clipboard and whenever something appears, just erase it. This will effectively disable copy/paste in the entire system. But why you need to do that is beyond me. If it's giving you thrills to write some kind of stupid malware, just do us a favor and get yourself a gf.

teycir8-May-09 4:52

8-May-09 4:52

The software I'm working on is a demand of a client to prevent the theft of data from his employees when they use a software. I'm not building this for myself.
If you have no idea on how to proceed to solve the problem, please don't post your dumb comments.

Member 10339078-May-09 4:58

8-May-09 4:58

In my defense - the idea of monitoring and erasing the clipboard wasn't that dumb, better that your hooking the mouse. Don't forget to disable the print screen as well, when you are at it.

teycir8-May-09 5:07

8-May-09 5:07

Printscreen and ctrl l ctrl r ctrl keys are disabled. U should have noticed that, I mentionned it in the post and it's easy to see in u read and understood a little bit the code.

Member 10339078-May-09 5:18

8-May-09 5:18

So in the end it's me who can't code. Do you really think anybody would read your several pages long code if it's supposed to be such a lame way of data protection?

teycir8-May-09 5:23

8-May-09 5:23

Yes u r unable to understand a single simple class and u r more a pain than a help with this post.

Member 10339078-May-09 7:39

8-May-09 7:39

Damn me. It's funny that I was the only one who actually suggested a solution, yet I am the one most incompetent. Unlike you, Mr. Hook'em all. Well, good luck tilting at windmills, let's just hope that when you finally manage to disable all the system functions, your client's data will be safe.
PS: Don't forget to make the whole screen black all the time your app is on, some smartass might make a picture of it with his cell phone.

teycir9-May-09 0:17