Lock keyboard and mouse or prevent user leaving window in C #

You can use the BlockInput , you will block the use of the keyboard and mouse .

using System.Runtime.InteropServices;

[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
public static extern void BlockInput([In, MarshalAs(UnmanagedType.Bool)]bool fBlockIt);

private void button1_Click(object sender, EventArgs e){
    BlockInput(true); 
}

Example taken from CodeProject .

But to use it, you must have privileges (from Windows Vista), create a manifest file and change the element requestedExecutionLevel to:

<requestedExecutionLevel level="requireAdministrator" uiAccess="false" />

When you run the program, the UAC window will appear to confirm the execution of the program with privileges.

Example of a manifest file:

<?xml version="1.0" encoding="utf-8" ?> 
<asmv1:assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1" 
    xmlns:asmv1="urn:schemas-microsoft-com:asm.v1" 
    xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <assemblyIdentity version="1.0.0.0" name="MyApplication" />
    <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">
        <security>
            <requestedPrivileges xmlns="urn:schemas-microsoft-com:asm.v3">
                 <requestedExecutionLevel level="requireAdministrator" uiAccess="false" />
            </requestedPrivileges>
        </security>
    </trustInfo>
</asmv1:assembly>

Alternative

An alternative is to use Hooks to intercept the events of the mouse and keyboard and manipulate the operation of these.

The articles below explain the use of Hooks in C #.

• Low-Level Keyboard Hook in C #
• Low-Level Mouse Hook in C #

Below are examples of how to undo the operation of the mouse and keyboard.

Mouse

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

        }
        // Importa as funções que serão usadas
        [DllImport("user32.dll")]
        private static extern IntPtr SetWindowsHookEx(int idHook,
            LowLevelMouseProc lpfn, IntPtr hMod, uint dwThreadId);

        [DllImport("user32.dll")]
        static extern bool UnhookWindowsHookEx(IntPtr hInstance);

        [DllImport("user32.dll")]
        static extern IntPtr CallNextHookEx(IntPtr idHook, int code, int wParam, IntPtr lParam);

        [DllImport("kernel32.dll")]
        static extern IntPtr LoadLibrary(string lpFileName);

        private delegate IntPtr LowLevelMouseProc(int code, IntPtr wParam, IntPtr lParam);

        private enum MouseMessages{
            WM_LBUTTONDOWN = 0x0201,
            WM_LBUTTONUP = 0x0202,
            WM_MOUSEMOVE = 0x0200,
            WM_MOUSEWHEEL = 0x020A,
            WM_RBUTTONDOWN = 0x0204,
            WM_RBUTTONUP = 0x0205
        }

        const int WH_MOUSE_LL = 14; // Tipo de hook que será usado

        private LowLevelMouseProc hook = hookProc;
        private static IntPtr hhook = IntPtr.Zero;

        public void SetHook(){
            IntPtr hInstance = LoadLibrary("User32");
            hhook = SetWindowsHookEx(WH_MOUSE_LL, hook, hInstance, 0); // Instala o hook para a interceptação dos eventos do mouse
        }

        public static void UnHook(){
            UnhookWindowsHookEx(hhook); // Remove o hook instalado
        }

        public static IntPtr hookProc(int code, IntPtr wParam, IntPtr lParam){
            // Se a mensagem recebida for > 0 e o clique do mouse for do botão esquerdo ou direito
            if (code >= 0 && MouseMessages.WM_LBUTTONDOWN == (MouseMessages)wParam || MouseMessages.WM_RBUTTONDOWN == (MouseMessages)wParam)
            {
                return (IntPtr)1; // Inibe o clique
            }
            else
                return CallNextHookEx(hhook, code, (int)wParam, lParam); // Passa para o próximo evento
        }

        private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e){
            UnHook(); // Ao fechar o form desintalamos o hook
        }

        private void Form1_Load(object sender, EventArgs e){
            SetHook(); // Ao iniciar instala o hook 
        }
    }
}

In the example above, the callback LowLevelMouseProc ", the system calls this function each time a new mouse-related event is to be released in

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

        }
        // Importa as funções que serão usadas
        [DllImport("user32.dll")]
        static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc callback, IntPtr hInstance, uint threadId);

        [DllImport("user32.dll")]
        static extern bool UnhookWindowsHookEx(IntPtr hInstance);

        [DllImport("user32.dll")]
        static extern IntPtr CallNextHookEx(IntPtr idHook, int code, int wParam, IntPtr lParam);

        [DllImport("kernel32.dll")]
        static extern IntPtr LoadLibrary(string lpFileName);

        private delegate IntPtr LowLevelKeyboardProc(int code, IntPtr wParam, IntPtr lParam);

        const int WH_KEYBOARD_LL = 13; // Tipo de hook que será usado
        const int WM_KEYDOWN = 0x100;  // Messagem usada para quando uma tecla for pressionada

        private LowLevelKeyboardProc hook = hookProc;
        private static IntPtr hhook = IntPtr.Zero;

        public void SetHook(){
            IntPtr hInstance = LoadLibrary("User32");
            hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hook, hInstance, 0); // Instala o hook para o teclado
        }

        public static void UnHook(){
            UnhookWindowsHookEx(hhook);
        }

        public static IntPtr hookProc(int code, IntPtr wParam, IntPtr lParam){
            if (code >= 0 && wParam == (IntPtr)WM_KEYDOWN){ // Quando uma tecla for pressionada
                return (IntPtr)1; // Inibe o funcionamento
            }
            else
                return CallNextHookEx(hhook, code, (int)wParam, lParam); // Passa para o próximo evento
        }

        private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            UnHook(); // Ao fechar o form desintala o hook
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            SetHook(); // Ao iniciar instala o hook
        }
    }
}