Today, when I was planning to write an article on Grid View. I got a message from a very good friend of mine who is asking to disable the special keys(Windows Keys) in his application. When I start researching on it, I was thinking that it can be done using e.KeyChar but unfortunately, it is not showing any information about windows keys.
So in this post I will explain you, how can we disable the special keys (in our case windows keys) in C# Application.
1. Crete a c# windows application project 2. On the code behind of your default form add the following references
1: using System.Diagnostics;
2: using System.Runtime.InteropServices;
3. Now before the constructor of your form place the following code.
1: // Structure contain information about low-level keyboard input event
2: [StructLayout(LayoutKind.Sequential)]
3: private struct KBDLLHOOKSTRUCT
4: {
5: public Keys key;
6: public int scanCode;
7: public int flags;
8: public int time;
9: public IntPtr extra;
10: }
11:
12: //System level functions to be used for hook and unhook keyboard input
13: private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
14: [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
15: private static extern IntPtr SetWindowsHookEx(int id, LowLevelKeyboardProc callback, IntPtr hMod, uint dwThreadId);
16: [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
17: private static extern bool UnhookWindowsHookEx(IntPtr hook);
18: [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
19: private static extern IntPtr CallNextHookEx(IntPtr hook, int nCode, IntPtr wp, IntPtr lp);
20: [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
21: private static extern IntPtr GetModuleHandle(string name);
22: [DllImport("user32.dll", CharSet = CharSet.Auto)]
23: private static extern short GetAsyncKeyState(Keys key);
24:
25:
26: //Declaring Global objects
27: private IntPtr ptrHook;
28: private LowLevelKeyboardProc objKeyboardProcess;
4. Now add the following code on your constructor.
1: public Form1
2: {
3: ProcessModule objCurrentModule = Process.GetCurrentProcess.MainModule; //Get Current Module
4: objKeyboardProcess = new LowLevelKeyboardProc(captureKey); //Assign callback function each time keyboard process
5: ptrHook = SetWindowsHookEx(13, objKeyboardProcess, GetModuleHandle(objCurrentModule.ModuleName), 0); //Setting Hook of Keyboard Process for current module
6:
7:
8: InitializeComponent;
9: }
5. Now Implement the callback function
1: private IntPtr captureKey(int nCode, IntPtr wp, IntPtr lp)
2: {
3: if (nCode >= 0)
4: {
5: KBDLLHOOKSTRUCT objKeyInfo = (KBDLLHOOKSTRUCT)Marshal.PtrToStructure(lp, typeof(KBDLLHOOKSTRUCT));
6:
7: if (objKeyInfo.key == Keys.RWin || objKeyInfo.key == Keys.LWin) // Disabling Windows keys
8: {
9: return (IntPtr)1;
10: }
11: }
12: return CallNextHookEx(ptrHook, nCode, wp, lp);
13: }
6. Now go to your designer class and replace your dispose method.
1: ///
2: /// Clean up any resources being used.
3: ///
4: /// true if managed resources should be disposed; otherwise, false.
5: protected override void Dispose(bool disposing)
6: {
7: if (disposing && (components!= null))
8: {
9:
10: components.Dispose;
11: }
12: if (ptrHook!= IntPtr.Zero)
13: {
14: UnhookWindowsHookEx(ptrHook);
15: ptrHook = IntPtr.Zero;
16: }
17: base.Dispose(disposing);
18: }
So, in this way we can stop the windows key operation till your application is running.You can find the Source code.