CODEWITHSUNDEEP
c#keyboardshortcut
roemel
roemel

Reputation: 3297

Disable keyboard using c#

I'm writing a program which is a webbrowser and disable all the keyboard shortcuts and keys. It is working but not perfectly. i found a thread where i got the code:

Blocking shortcut keys using c#

And my problem is: everytime i open the program, first i have to click in the window or use a shortcut and click in the window again. and after that, it works. but it have to work when i open it so i don't have to click two times...

somebody got an idea?

cheers

EDIT: Okay. I try to explain my problem in another way:

First I open the program. And then I should not be able to press any keys like Win+Tab etc. But I am still able to press keys. Then if I click in the window of my program, press a key and click in the window again, it works. But i want that the program works when I open it so I don't have to click in the window first. I got some code here:

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

namespace Browser
{
    public partial class Form1 : Telerik.WinControls.UI.RadForm
    {
        public Form1()
        {
            InitializeComponent();
        }

        private delegate int LowLevelKeyboardProcDelegate(int nCode, int
           wParam, ref KBDLLHOOKSTRUCT lParam);

        [DllImport("user32.dll", EntryPoint = "SetWindowsHookExA", CharSet = CharSet.Ansi)]
        private static extern int SetWindowsHookEx(
           int idHook,
           LowLevelKeyboardProcDelegate lpfn,
           int hMod,
           int dwThreadId);

        [DllImport("user32.dll")]
        private static extern int UnhookWindowsHookEx(int hHook);

        [DllImport("user32.dll", EntryPoint = "CallNextHookEx", CharSet = CharSet.Ansi)]
        private static extern int CallNextHookEx(
            int hHook, int nCode,
            int wParam, ref KBDLLHOOKSTRUCT lParam);

        const int WH_KEYBOARD_LL = 13;
        private int intLLKey;
        private KBDLLHOOKSTRUCT lParam;

        private struct KBDLLHOOKSTRUCT
        {
            public int vkCode;
            int scanCode;
            public int flags;
            int time;
            int dwExtraInfo;
        }

        private int LowLevelKeyboardProc(
            int nCode, int wParam,
            ref KBDLLHOOKSTRUCT lParam)
        {
            bool blnEat = false;
            switch (wParam)
            {
                case 256:
                case 257:
                case 260:
                case 261:
                    //Alt+Tab, Alt+Esc, Ctrl+Esc, Windows Key
                    if (((lParam.vkCode == 9) && (lParam.flags == 32)) ||
                    ((lParam.vkCode == 27) && (lParam.flags == 32)) || ((lParam.vkCode ==
                    27) && (lParam.flags == 0)) || ((lParam.vkCode == 91) && (lParam.flags
                    == 1)) || ((lParam.vkCode == 92) && (lParam.flags == 1)) || ((true) &&
                    (lParam.flags == 32)))
                    {
                        blnEat = true;
                    }
                    break;
            }

            if (blnEat)
                return 1;
            else return CallNextHookEx(0, nCode, wParam, ref lParam);

        }

        private void KeyboardHook(object sender, EventArgs e)
        {
            intLLKey = SetWindowsHookEx(WH_KEYBOARD_LL, new LowLevelKeyboardProcDelegate(LowLevelKeyboardProc),
                       System.Runtime.InteropServices.Marshal.GetHINSTANCE(
                       System.Reflection.Assembly.GetExecutingAssembly().GetModules()[0]).ToInt32(), 0);
        }

        private void ReleaseKeyboardHook()
        {
            intLLKey = UnhookWindowsHookEx(intLLKey);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Maximized;
        }

        private void webBrowser1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
        {
            KeyboardHook(this, e);
        }
    }
}

I hope you know what I mean now Cheers

Upvotes: 2

Views: 23599

Answers (1)

roemel
roemel

Reputation: 3297

For all who have the same problem, I got the solution:

You just have to put KeyboardHook(this, e); in Form1_Load(). So the Form1_Load() should now look like this:

private void Form1_Load(object sender, EventArgs e)
{
    this.WindowState = FormWindowState.Maximized;
    KeyboardHook(this, e);
}

Reason: Everytime the program starts, it should block every combination like Alt+F4 etc. Before we put KeyboardHook(this, e); into Form1_Load();, the program just blocks the key combinations if a key is pressed in webBrowser1

(webBrowser1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e))

If you put it into Form1_Load();, it starts blocking combinations immediately.

Of course, this won't work with Win+L or Ctrl+Alt+Del because they are hotkeys.

I hope I could help everyone who have the same problem :)

Cheers

Upvotes: 3

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