C#•9mo ago

Sending key presses to other applications without Windows Forms

Because I'm working with the Godot game engine for the graphics interface, I'm kinda restricted with their Mono implementation. That prevents me from using the windows forms stuff. So I've tried the solutions using user32.dll but they only work when I move my mouse. I assume that is happening because of the following: I have a touchscreen with a button. When that button is pressed, there should be the according key action. I think that because of the touch input, it's doing some funky stuff with the window focus and that results in the behaviour described above. Code looks as follows:

34 Replies

Kaenguruu24OP•9mo ago

c#
using System;
using System.Linq;
using WindowsInput.Native;
using System.Runtime.InteropServices;
using System.Collections.Generic;

public class KeyboardSimulator
{
    [DllImport("user32.dll")]
    static extern uint SendInput(uint nInputs, [MarshalAs(UnmanagedType.LPArray), In] INPUT[] pInputs, int cbSize);

    [StructLayout(LayoutKind.Sequential)]
    public struct INPUT
    {
        public uint type;
        public InputUnion U;
        public static int Size
        {
            get { return Marshal.SizeOf(typeof(INPUT)); }
        }
    }

    [StructLayout(LayoutKind.Explicit)]
    public struct InputUnion
    {
        [FieldOffset(0)]
        public MOUSEINPUT mi;
        [FieldOffset(0)]
        public KEYBDINPUT ki;
        [FieldOffset(0)]
        public HARDWAREINPUT hi;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct MOUSEINPUT
    {
        public int dx;
        public int dy;
        public uint mouseData;
        public uint dwFlags;
        public uint time;
        public IntPtr dwExtraInfo;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct KEYBDINPUT
    {
        public ushort wVk;
        public ushort wScan;
        public uint dwFlags;
        public uint time;
        public IntPtr dwExtraInfo;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct HARDWAREINPUT
    {
        public uint uMsg;
        public ushort wParamL;
        public ushort wParamH;
    }
}

c#
using System;
using System.Linq;
using WindowsInput.Native;
using System.Runtime.InteropServices;
using System.Collections.Generic;

public class KeyboardSimulator
{
    [DllImport("user32.dll")]
    static extern uint SendInput(uint nInputs, [MarshalAs(UnmanagedType.LPArray), In] INPUT[] pInputs, int cbSize);

    [StructLayout(LayoutKind.Sequential)]
    public struct INPUT
    {
        public uint type;
        public InputUnion U;
        public static int Size
        {
            get { return Marshal.SizeOf(typeof(INPUT)); }
        }
    }

    [StructLayout(LayoutKind.Explicit)]
    public struct InputUnion
    {
        [FieldOffset(0)]
        public MOUSEINPUT mi;
        [FieldOffset(0)]
        public KEYBDINPUT ki;
        [FieldOffset(0)]
        public HARDWAREINPUT hi;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct MOUSEINPUT
    {
        public int dx;
        public int dy;
        public uint mouseData;
        public uint dwFlags;
        public uint time;
        public IntPtr dwExtraInfo;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct KEYBDINPUT
    {
        public ushort wVk;
        public ushort wScan;
        public uint dwFlags;
        public uint time;
        public IntPtr dwExtraInfo;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct HARDWAREINPUT
    {
        public uint uMsg;
        public ushort wParamL;
        public ushort wParamH;
    }
}

c#
public void SimulateKeyPresses(string keys, string target)
    {
        const uint INPUT_KEYBOARD = 1;
        const uint KEYEVENTF_KEYUP = 0x0002;

        var keyList = keys.Split(' ').Select(k => Enum.Parse<VirtualKeyCode>(k.ToUpper())).ToList();
        ushort KeyCode = 0;

        if (keyList.Count == 0) return;

        List<INPUT> inputs = new List<INPUT>();

        // Press down each key
        foreach (var key in keyList)
        {
            KeyCode = (ushort)key;
            inputs.Add(new INPUT
            {
                type = INPUT_KEYBOARD,
                U = new InputUnion
                {
                    ki = new KEYBDINPUT
                    {
                        wVk = KeyCode,
                        dwFlags = 0
                    }
                }
            });
        }

        // Release each key
        foreach (var key in keyList)
        {
            KeyCode = (ushort)key;
            inputs.Add(new INPUT
            {
                type = INPUT_KEYBOARD,
                U = new InputUnion
                {
                    ki = new KEYBDINPUT
                    {
                        wVk = KeyCode,
                        dwFlags = KEYEVENTF_KEYUP
                    }
                }
            });
        }

        // Send the input events
        SendInput((uint)inputs.Count, inputs.ToArray(), INPUT.Size);
    }

c#
public void SimulateKeyPresses(string keys, string target)
    {
        const uint INPUT_KEYBOARD = 1;
        const uint KEYEVENTF_KEYUP = 0x0002;

        var keyList = keys.Split(' ').Select(k => Enum.Parse<VirtualKeyCode>(k.ToUpper())).ToList();
        ushort KeyCode = 0;

        if (keyList.Count == 0) return;

        List<INPUT> inputs = new List<INPUT>();

        // Press down each key
        foreach (var key in keyList)
        {
            KeyCode = (ushort)key;
            inputs.Add(new INPUT
            {
                type = INPUT_KEYBOARD,
                U = new InputUnion
                {
                    ki = new KEYBDINPUT
                    {
                        wVk = KeyCode,
                        dwFlags = 0
                    }
                }
            });
        }

        // Release each key
        foreach (var key in keyList)
        {
            KeyCode = (ushort)key;
            inputs.Add(new INPUT
            {
                type = INPUT_KEYBOARD,
                U = new InputUnion
                {
                    ki = new KEYBDINPUT
                    {
                        wVk = KeyCode,
                        dwFlags = KEYEVENTF_KEYUP
                    }
                }
            });
        }

        // Send the input events
        SendInput((uint)inputs.Count, inputs.ToArray(), INPUT.Size);
    }

leowest•9mo ago

hmmm what, I am not sure I understood what is going on, you're using godot to write an application and not a game and your complaining it lack certain supports u would normally have?

Kaenguruu24OP•9mo ago

I'm not complaining I'm simply stating that I'm having issues. But effectively, yes, I'm saying that I'm missing certain features due to the fact that I'm using Godot for this

leowest•9mo ago

ok but you're using it to write an application instead of a game? why was there no framework that could aid u?

Kaenguruu24OP•9mo ago

Cause I don't have much time outside of school to learn something entirely new just because of this one thing. I tried Windows Forms once and hated it and I am simply not at a point where I want to invest significant time into this. It's a project for myself only and I'm not gonna rewrite everything because of this

leowest•9mo ago

That prevents me from using the windows forms stuff.

by that I assume you mean using winform libraries?

Kaenguruu24OP•9mo ago

Yes, at least thats what I've experienced. I tried adding the System.Windows.Forms dll to the project but it just won't compile. I've read that it's supposedly because of the way Godot integrates C#

leowest•9mo ago

yes so you're trying to sendkeys from your godot to another application?

Kaenguruu24OP•9mo ago

Yes. Imagine it as a sort of digital stream deck where pressing a button should execute a key combination (or just a single key) on another program

leowest•9mo ago

sure but streamdeck is linux base what you're doing is accessing windows only api to send keys so it would not work on any other platform

Kaenguruu24OP•9mo ago

Yes and as I mentioned it's for personal use only and I'm on Windows so thats not a problem

leowest•9mo ago

and what are u trying to control because depending on what this would not work regardless not it being an issue with touch screen

Kaenguruu24OP•9mo ago

all sorts of applications. Discord, Firefox, games like DCS or ETS 2

leowest•9mo ago

so essentially you want to send keys to other games so type of automation

Kaenguruu24OP•9mo ago

yes

Buddy•9mo ago

StreamDeck is hardware not Software

Kaenguruu24OP•9mo ago

I'm aware, thank you

leowest•9mo ago

streamdeck doesn't matter he wants it for windows and at this point I am not sure I can further assist him due to break of TOS

Buddy•9mo ago

Why did you choose to make it in Godot may I ask? Like why a game engine for an app? Considering the game engine redraws even if the UI hasn't been changed, so you basically waste resources continuously, which is important for streamers.

Kaenguruu24OP•9mo ago

See the previous conversation. I know how to use it, it provides a quick way to set up a graphical user interface and my experience with winforms was horrible

Buddy•9mo ago

Avalonia is an option

leowest•9mo ago

@Citizen of Pluto he is writing bots to automate games

Kaenguruu24OP•9mo ago

honestly I don't care about that little performance impact

Buddy•9mo ago

It isn't little.

Kaenguruu24OP•9mo ago

I have not experienced even the slightest drop in fps while the application was running. It's a personal use project only so nobody else is impacted by this

Buddy•9mo ago

You do you, but as Leowest pointed out. Unfortunately we cannot help unless you have proof that you are not automating games that forbids it by the ToS.

Kaenguruu24OP•9mo ago

So you are not sure whether I'm trying to cheat is basically what you are saying?

Nox•9mo ago

@Kaenguruu24 We don't allow help for any type of game automation because of the gray area. Please understand it's difficult to discern the rare case where it's okay compared to the thousands of times it's not allowed and why it's a blanket statement.

Kaenguruu24OP•9mo ago

Kinda sad im gonna be honest. Have a good day then

Nox•9mo ago

Thank you for understanding, sorry about that

leowest•9mo ago

well he left the server heh

Nox•9mo ago

s'alright. He seemed reasonable so I didn't nuke immediately.

leowest•9mo ago

yeah I mean its fine, I just didnt proceed to help him because he clearly stated it was for games and the reason I was suspicious was because the game had protection against sending keys thus why it was not working and he thou it was something else 😛

oke•9mo ago

oof

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Sending key presses to other applications without Windows Forms