How do I fix the error with this code C#

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I try to create key presser for game it require to press (Space + number) to do some action i tried this code

C#

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

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {

        [DllImport("user32.dll", SetLastError = true)]
        static extern void keybd_event(byte bVk, byte bScan, int dwFlags, int dwExtraInfo);

        [DllImport("user32.dll")]
        public static extern IntPtr PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

        const uint WM_KEYDOWN = 0x100;
        const uint WM_KEYUP = 0x101;

        public Form1()
        {
            InitializeComponent();
            LoadProcess();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Process p = (Process)comboBox1.SelectedItem;
            keybd_event((byte)Keys.Space, 0, 1, 0);
            Thread.Sleep(50);
            PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);
            PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);
            keybd_event((byte)Keys.Space, 0, 0, 0);
        }

        private void LoadProcess()
        {
            comboBox1.Items.Clear();
            comboBox1.DisplayMember = "MainWindowTitle";
            foreach (Process item in Process.GetProcesses())
            {
                try
                {
                    if (!string.IsNullOrEmpty(item.MainWindowTitle))
                        comboBox1.Items.Add(item);
                }
                catch { }
            }
        }
    }
}

it work but keep pressing space

when i try to release it by this command

C#

keybd_event((byte)Keys.Space, 0, 2, 0);

the application keep repeat pressing all the keys

and if didn't add this line the space didn't reals

how to fix this?

What I have tried:

C#

//this code problem is repeat all the keys
const int KeyDown = 0x0001;
const int KeyUp = 0x0002;
.......

private void button1_Click(object sender, EventArgs e)
        {
            Process p = (Process)comboBox1.SelectedItem;
            keybd_event((byte)Keys.Space, 0, KeyDown, 0);
            Thread.Sleep(50);
            PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);
            PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);
            keybd_event((byte)Keys.Space, 0, KeyUp, 0);
        }

C#

//this code problem is not release the space
const uint WM_KEYDOWN = 0x100;
const uint WM_KEYUP = 0x101;

.........

private void button1_Click(object sender, EventArgs e)
        {
            Process p = (Process)comboBox1.SelectedItem;
            keybd_event((byte)Keys.Space, 0, (int)WM_KEYDOWN, 0);
            Thread.Sleep(50);
            PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);
            PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);
            keybd_event((byte)Keys.Space, 0, (int)WM_KEYUP, 0);
        }

C#

//this code problem is not release the space
const uint WM_KEYDOWN = 0x100;
const uint WM_KEYUP = 0x101;

.........

private void button1_Click(object sender, EventArgs e)
        {
            Process p = (Process)comboBox1.SelectedItem;
            keybd_event((byte)Keys.Space, 0, (int)WM_KEYDOWN, 0);
            Thread.Sleep(50);
            PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);
            PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);
            keybd_event((byte)Keys.Space, 0, 0, 0);
        }

C#

//this code problem is it do nothing
const uint WM_KEYDOWN = 0x100;
const uint WM_KEYUP = 0x101;

.........

private void button1_Click(object sender, EventArgs e)
        {
            Process p = (Process)comboBox1.SelectedItem;
            keybd_event((byte)Keys.Space, 0, 1, 0);
            Thread.Sleep(50);
            keybd_event((byte)Keys.D1, 0, 1, 0);
            keybd_event((byte)Keys.D1, 0, 2, 0);
            keybd_event((byte)Keys.Space, 0, 2, 0);
        }

C#

//this code problem is it do nothing
const uint WM_KEYDOWN = 0x100;
const uint WM_KEYUP = 0x101;
const int KeyDown = 0x0001;
const int KeyUp = 0x0002;

.........

private void button1_Click(object sender, EventArgs e)
        {
            keybd_event((byte)Keys.Space, 0, KeyDown, 0);
            Thread.Sleep(50);
            keybd_event((byte)Keys.D1, 0, KeyDown, 0);
            Thread.Sleep(50);
            keybd_event((byte)Keys.D1, 0, KeyUp, 0);
            keybd_event((byte)Keys.Space, 0, KeyUp, 0);
        }

Posted 3-Feb-18 0:54am

Member 7912784

Updated 5-Feb-18 7:19am

Add a Solution

2 solutions

Solution 1

See the remark at the top of the documentation for keybd_event function (Windows)[^].

Posted 3-Feb-18 1:30am

Richard MacCutchan

Comments

Member 7912784 3-Feb-18 8:28am

if u mean {Note This function has been superseded. Use SendInput instead.}

i try SendInput and the same error the application keep repeat the keys

Richard MacCutchan 3-Feb-18 8:46am

The values that you are sending to keybd_event are wrong. Look at the documentation more closely.

Member 7912784 3-Feb-18 9:40am

const uint WM_KEYDOWN = 0x100;
const uint WM_KEYUP = 0x101;
const int KeyDown = 0x0001;
const int KeyUp = 0x0002;
const byte VK_SPACE = 0x20;
const byte SpaceSC = 39;

private void button1_Click(object sender, EventArgs e)
{
Process p = (Process)comboBox1.SelectedItem;
keybd_event(VK_SPACE, SpaceSC, KeyDown, 0);
Thread.Sleep(50);
PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);
PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);
keybd_event(VK_SPACE, SpaceSC, KeyUp, 0);
}

code u please point to the wrong values in this code because it keep repeat the keys

Richard MacCutchan 3-Feb-18 11:14am

You are sending an invalid value for KeyDown - please read the documentation again.

Member 7912784 3-Feb-18 15:14pm

const uint Key_Down = 0x0001;
const uint Key_Up = 0x0002;
const byte VK_SPACE = 0x20;
const byte SpaceSC = 39;

private void button1_Click(object sender, EventArgs e)
{
Process p = (Process)comboBox1.SelectedItem;
keybd_event(VK_SPACE, 0x45, Key_Down | 0, 0);
Thread.Sleep(50);
PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);
PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);
keybd_event(VK_SPACE, 0x45, Key_Down| Key_Up, 0);
}

--------------------------------------------------------------

const uint Key_Down = 0x0001;
const uint Key_Up = 0x0002;
const byte VK_SPACE = 0x20;
const byte SpaceSC = 39;

private void button1_Click(object sender, EventArgs e)
{
Process p = (Process)comboBox1.SelectedItem;
keybd_event(VK_SPACE, 0, 0, 0);
Thread.Sleep(50);
PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);
PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);
keybd_event(VK_SPACE, 0, Key_Up, 0);
}

-------------------------------------------------------------

const uint Key_Down = 0x0001;
const uint Key_Up = 0x0002;
const byte VK_SPACE = 0x20;
const byte SpaceSC = 39;

private void button1_Click(object sender, EventArgs e)
{
Process p = (Process)comboBox1.SelectedItem;
keybd_event(VK_SPACE, 0, Key_Down , 0);
Thread.Sleep(50);
PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);
PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);
keybd_event(VK_SPACE, 0, Key_Up, 0);
}

----------------------------------------------------------------

i try all that and more but same error and msdn say the the key down value is
KEYEVENTF_EXTENDEDKEY
0x0001
as my Key_Down i didn't get the error in my code why it keep repeat all the pressing

Member 7912784 4-Feb-18 8:49am

i try to use third part dll inputsimulator & inputsimulator plus

InputSimulator sss = new InputSimulator();
Process p = (Process)comboBox1.SelectedItem;            sss.Keyboard.KeyDown(VirtualKeyCode.SPACE);            Thread.Sleep(50);            PostMessage(p.MainWindowHandle, WM_KEYDOWN, (IntPtr)Keys.D1, IntPtr.Zero);            PostMessage(p.MainWindowHandle, WM_KEYUP, (IntPtr)Keys.D1, IntPtr.Zero);            sss.Keyboard.KeyUp(VirtualKeyCode.SPACE);

same error keep repeat the pressing

Richard MacCutchan 4-Feb-18 9:13am

It really is time to see what is going on in your code. And that is something only you can do, by using your debugger.

Member 7912784 4-Feb-18 10:01am

when i remove the line :

keybd_event(VK_SPACE, 0, Key_Up, 0);

the app stop repeat the code put the space didn't release i didn't now why

Member 7912784 4-Feb-18 10:58am

i use debugger in the first it show nothing just as normal method start and finished
no repeat or something

my last did is that

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

namespace KeysWithModefier
{
    public class Class2
    {
        private Process _p;

        [DllImport("user32.dll", SetLastError = true)]
        static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, int dwExtraInfo);

        [DllImport("user32.dll")]
        public static extern IntPtr PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

        const uint WM_KEYDOWN = 0x100;
        const uint WM_KEYUP = 0x101;
        const uint Key_Down = 0x0001;
        const uint Key_Up = 0x0002;

        public Class2(Process p)
        {
            _p = p;
        }

        public void SendKeyWithModefir(Keys ModKey, Keys PressKey)
        {
            keybd_event((byte)ModKey, 0, 0, 0);
            Thread.Sleep(50); ;
            PostMessage(_p.MainWindowHandle, WM_KEYDOWN, (IntPtr)(PressKey), (IntPtr)(0));
            PostMessage(_p.MainWindowHandle, WM_KEYUP, (IntPtr)(PressKey), (IntPtr)(0));
            keybd_event((byte)ModKey, 0, Key_Up, 0);
        }

        ~Class2()
        {
            GC.Collect();
        }
    }
}

----------------------------------------------------------------------------------

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows.Forms;
using KeysWithModefier;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            LoadProcess();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Class2 ccc = new Class2((Process)comboBox1.SelectedItem);
            ccc.SendKeyWithModefir(Keys.Space, Keys.D1);
            ccc = null;
        }

        private void LoadProcess()
        {
            comboBox1.Items.Clear();
            comboBox1.DisplayMember = "MainWindowTitle";
            foreach (Process item in Process.GetProcesses())
            {
                try
                {
                    if (!string.IsNullOrEmpty(item.MainWindowTitle))
                        comboBox1.Items.Add(item);
                }
                catch { }
            }
        }
    }
}

but it also same the keys keep pressing tell i close the app i ideas how to make this class like app closed with out close it?

Richard MacCutchan 4-Feb-18 12:19pm

I have not used keybd_event, but it may be that mixing this with PostMessage is causing the problem. But see also the latest comment in your other question.

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Member 7912784 · Accepted Answer · 2018-02-05T07:19:00

i find way to solve it

C#

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

namespace SendKeysWithModefire
{
   public class KeysTest
    {
        [DllImport("user32.dll", SetLastError = true)]
        static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, int dwExtraInfo);

        [DllImport("user32.dll")]
        public static extern IntPtr PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

        const uint WM_KEYDOWN = 0x100;
        const uint WM_KEYUP = 0x101;
        const uint Key_Down = 0x0001;
        const uint Key_Up = 0x0002;
        private volatile bool _shouldStop;
        private Process _sroProcess;
        private Keys _modefirKey;
        private Keys _pressKey;

        public KeysTest(Process targetSro,Keys modKey,Keys pressKey)
        {
            _sroProcess = targetSro;
            _modefirKey = modKey;
            _pressKey = pressKey;
        }

        public void SendKeys()
        {
            SendKeyWithModefir(_sroProcess, (byte)_modefirKey, (byte)_pressKey);
        }

        public void SendKeyWithModefir(Process _p, byte ModKey, byte PressKey)
        {
            while (!_shouldStop)
            {
                keybd_event(ModKey, 0, Key_Down, 0);
                Thread.Sleep(50);
                PostMessage(_p.MainWindowHandle, WM_KEYDOWN, (IntPtr)(PressKey), (IntPtr)(0));
                PostMessage(_p.MainWindowHandle, WM_KEYUP, (IntPtr)(PressKey), (IntPtr)(0));
                Thread.Sleep(50);
                keybd_event(ModKey, 0, Key_Up, 0);
            }
        }

        public void RequestStop()
        {
            _shouldStop = true;
        }

        ~KeysTest()
        {
            GC.Collect();
        }
    }
}

and that's the call for it

C#

private KeysTest sendingKeys;
private Thread startSending;

...............

//that code send Left Control + 1
//s is the target process
sendingKeys = new KeysTest(s, Keys.LControlKey, Keys.D1);
startSending = new Thread(sendingKeys.SendKeys); 
startSending.Start();
while (!startSending.IsAlive) ;
Thread.Sleep(2000);
sendingKeys.RequestStop();
startSending.Join();
startSending.Abort();