Preventing form to do things

Question

I want my Form frmMainMenu to disable stuffs. the first thing I did is set it to maximized and remove the minimize & maximize on control. When I drag the form it automatically minimized, also when I double click the controlBox it also minimize. I also want the form to prevent movement. and lastly i want to disable the alt + tab on my form.

I have some code here for disabling movement.

protected override void WndProc(ref Message message)
    {
        const int WM_SYSCOMMAND = 0x0112;
        const int SC_MOVE = 0xF010;
        switch (message.Msg)
        {
            case WM_SYSCOMMAND:
                int command = message.WParam.ToInt32() & 0xfff0;
                if (command == SC_MOVE)
                    return;
                break;
        }

        base.WndProc(ref message);
    }

here is for double click

 private const int WM_NCLBUTTONDBLCLK = 0x00A3; 

    protected override void WndProc(ref Message m)
    {
        if (m.Msg == WM_NCLBUTTONDBLCLK)
        {
            m.Result = IntPtr.Zero;
            return;
        }
        base.WndProc(ref m);
    }

i dont have a code for drag and alt + tab and i cant put those two in my form because the have the same parameter WndProc.

Answer 1

Do the following steps:

1. Create a Form
2. Set FormBorderStyle to FixedSingle
3. Set MinimizeBox to false
4. Set MaximizeBox to false
5. Set TopMost to true
6. Handle Load, FormClosing and DeActivate events of your form.
7. Write this code in your form class:

Code:

public partial class Form1: Form
{
    public Form1()
    {
        InitializeComponent();
    }

    // Structure contain information about low-level keyboard input event 
    [StructLayout(LayoutKind.Sequential)]
    private struct KBDLLHOOKSTRUCT
    {
        public Keys key;
        public int scanCode;
        public int flags;
        public int time;
        public IntPtr extra;
    }
    //System level functions to be used for hook and unhook keyboard input  
    private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr SetWindowsHookEx(int id, LowLevelKeyboardProc callback, IntPtr hMod, uint dwThreadId);
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern bool UnhookWindowsHookEx(IntPtr hook);
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr CallNextHookEx(IntPtr hook, int nCode, IntPtr wp, IntPtr lp);
    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr GetModuleHandle(string name);
    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    private static extern short GetAsyncKeyState(Keys key);
    //Declaring Global objects     
    private IntPtr ptrHook;
    private LowLevelKeyboardProc objKeyboardProcess;

    private IntPtr captureKey(int nCode, IntPtr wp, IntPtr lp)
    {
        if (nCode >= 0)
        {
            KBDLLHOOKSTRUCT objKeyInfo = (KBDLLHOOKSTRUCT)Marshal.PtrToStructure(lp, typeof(KBDLLHOOKSTRUCT));

            // Disabling Windows keys 

            if (objKeyInfo.key == Keys.RWin || objKeyInfo.key == Keys.LWin || objKeyInfo.key == Keys.Tab && HasAltModifier(objKeyInfo.flags) || objKeyInfo.key == Keys.Escape && (ModifierKeys & Keys.Control) == Keys.Control)
            {
                return (IntPtr)1; // if 0 is returned then All the above keys will be enabled
            }
        }
        return CallNextHookEx(ptrHook, nCode, wp, lp);
    }

    bool HasAltModifier(int flags)
    {
        return (flags & 0x20) == 0x20;
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        ProcessModule objCurrentModule = Process.GetCurrentProcess().MainModule;
        objKeyboardProcess = new LowLevelKeyboardProc(captureKey);
        ptrHook = SetWindowsHookEx(13, objKeyboardProcess, GetModuleHandle(objCurrentModule.ModuleName), 0);
    }
    private void Form1_FormClosing(object sender, FormClosingEventArgs e)
    {
        e.Cancel = true;
    }

    protected override void WndProc(ref Message message)
    {
        const int WM_SYSCOMMAND = 0x0112;
        const int SC_MOVE = 0xF010;

        switch (message.Msg)
        {
            case WM_SYSCOMMAND:
                int command = message.WParam.ToInt32() & 0xfff0;
                if (command == SC_MOVE)
                    return;
                break;
        }

        base.WndProc(ref message);
    }
    private void Form1_Deactivate(object sender, EventArgs e)
    {
        this.Activate();
    }
}

Notes:

• The code for disable Win and Alt + Tab has taken from this post, Thanks to the author.

• The code for preventing move, has taken from this post, Thanks to the author.

• Don't Forgt to add usings:

Usings:

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