C#•2y ago

❔ making a consoleapp stop when pressing a key

how do i make a ConsoleApp stop when pressing WHILE running, i dont want it to stop i want the program to continue working until a chosen key is pressed

21 Replies

ElmishhOP•2y ago

i have a program that moves my mouse every few seconds and i want a failsafe in case it doesnt stop when its supposed to

Jester•2y ago

when you press a chosen key in the console or just anywhere?

Jester•2y ago

https://stackoverflow.com/a/5620647

Stack Overflow

Non-Blocking read from standard I/O in C#

I want a non-blocking read function from console. How do I write that in C#?

Jester•2y ago

or use a hotkey if you want to be able to stop it even when the console isnt the active window (windows only, you need to dll import it)

Jester•2y ago

https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-registerhotkey

RegisterHotKey function (winuser.h) - Win32 apps

Defines a system-wide hot key.

Jester•2y ago

first you register a hotkey, and then in the loop of your application you can use PeekMessage to see if the hotkey has been pressed

ElmishhOP•2y ago

that shows C++ code but i want to be able to just stop even while console isnt active

Monsieur Wholesome•2y ago

You can run your funky code concurrently via a Task, and in the main Program you do a lil loop Actually, no that requires you to have the console open in front of you which thinking about your use case of moving the mouse around wildly, you will likely not have

Monsieur Wholesome•2y ago

Checkout Mouse + Keyboard Hook / "Keylogger" https://github.com/TolikPylypchuk/SharpHook

GitHub

GitHub - TolikPylypchuk/SharpHook: SharpHook provides a cross-platf...

SharpHook provides a cross-platform global keyboard and mouse hook for .NET, and the ability to simulate input events - GitHub - TolikPylypchuk/SharpHook: SharpHook provides a cross-platform global...

Jester•2y ago

maybe a bit overkill but a nice abstraction

Monsieur Wholesome•2y ago

How else will you establish a global keylogger? Is it that easy? Enlighten me

Jester•2y ago

well if its just 1 key to stop the application, a hotkey is easier to do

Monsieur Wholesome•2y ago

Wouldnt dare messing with P/Invoke and prefer a C# lib "just for a hotkey"

Jester•2y ago

another way to do a global keylogger is instead of creating a hook is using raw input here, i wrote this example of how you could use a hotkey (windows only)

using System;
using System.Runtime.InteropServices;
using System.Threading;

const int MOD_CONTROL = 0x2;
const int MOD_NOREPEAT = 0x4000;
const int PM_REMOVE = 0x1;
const int WM_HOTKEY = 0x0312;

// register hotkey ctrl+p
RegisterHotKey(
    IntPtr.Zero,
    1,
    MOD_CONTROL | MOD_NOREPEAT,
    'P'
);

while (true)
{
    // the logic of your program
    Console.WriteLine("Hello!");
    Thread.Sleep(1000);

    // check if there is a message available
    if (PeekMessage(out Msg msg, IntPtr.Zero, 0, 0, PM_REMOVE) > 0)
    {
        if (msg.message == WM_HOTKEY) // there was a message for to tell us the hotkey was pressed!
        {
            break; // we can stop now
        }
    }
}

return;

// some stuff to use the C functions from windows in our C#

// https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-registerhotkey
[DllImport("user32")]
static extern int RegisterHotKey(
  IntPtr hWnd,
  int id,
  uint fsModifiers,
  uint vk
);

// https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-peekmessagew
[DllImport("user32", CharSet = CharSet.Unicode, EntryPoint = "PeekMessageW")]
static extern int PeekMessage(
    out Msg lpMsg,
    IntPtr hWnd,
    uint wMsgFilterMin,
    uint wMsgFilterMax,
    uint wRemoveMsg
);

// https://learn.microsoft.com/en-us/windows/win32/api/winuser/ns-winuser-msg
[StructLayout(LayoutKind.Sequential)]
struct Msg
{
    public IntPtr hwnd;
    public uint message;
    public nuint wParam;
    public nuint lParam;
    public uint time;
    public int ptx;
    public int pty;
    public uint lPrivate;
}

using System;
using System.Runtime.InteropServices;
using System.Threading;

const int MOD_CONTROL = 0x2;
const int MOD_NOREPEAT = 0x4000;
const int PM_REMOVE = 0x1;
const int WM_HOTKEY = 0x0312;

// register hotkey ctrl+p
RegisterHotKey(
    IntPtr.Zero,
    1,
    MOD_CONTROL | MOD_NOREPEAT,
    'P'
);

while (true)
{
    // the logic of your program
    Console.WriteLine("Hello!");
    Thread.Sleep(1000);

    // check if there is a message available
    if (PeekMessage(out Msg msg, IntPtr.Zero, 0, 0, PM_REMOVE) > 0)
    {
        if (msg.message == WM_HOTKEY) // there was a message for to tell us the hotkey was pressed!
        {
            break; // we can stop now
        }
    }
}

return;

// some stuff to use the C functions from windows in our C#

// https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-registerhotkey
[DllImport("user32")]
static extern int RegisterHotKey(
  IntPtr hWnd,
  int id,
  uint fsModifiers,
  uint vk
);

// https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-peekmessagew
[DllImport("user32", CharSet = CharSet.Unicode, EntryPoint = "PeekMessageW")]
static extern int PeekMessage(
    out Msg lpMsg,
    IntPtr hWnd,
    uint wMsgFilterMin,
    uint wMsgFilterMax,
    uint wRemoveMsg
);

// https://learn.microsoft.com/en-us/windows/win32/api/winuser/ns-winuser-msg
[StructLayout(LayoutKind.Sequential)]
struct Msg
{
    public IntPtr hwnd;
    public uint message;
    public nuint wParam;
    public nuint lParam;
    public uint time;
    public int ptx;
    public int pty;
    public uint lPrivate;
}