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How can I check and toggle Num-Lock programmatically in C #?

I would like to programmatically check the value and be able to toggle num-lock. What's the easiest way to do this in C #?

The reason is that I want to check num-lock "ON" when the program starts.

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Check How to programmatically enable Numlock key



using System;
using System.Runtime.InteropServices;

class SetNumlockKeyOn
{
    [StructLayout(LayoutKind.Sequential)]
    public struct INPUT
    {
        internal int type;
        internal short wVk;
        internal short wScan;
        internal int dwFlags;
        internal int time;
        internal IntPtr dwExtraInfo;
        int dummy1;
        int dummy2;
        internal int type1;
        internal short wVk1;
        internal short wScan1;
        internal int dwFlags1;
        internal int time1;
        internal IntPtr dwExtraInfo1;
        int dummy3;
        int dummy4;
}
[DllImport("user32.dll")]
static extern int SendInput(uint nInputs, IntPtr pInputs, int cbSize);

public static void SetNumlockOn()
{
    const int mouseInpSize = 28;//Hardcoded size of the MOUSEINPUT tag !!!
    INPUT input = new INPUT();
    input.type = 0x01; //INPUT_KEYBOARD
    input.wVk = 0x90; //VK_NUMLOCK
    input.wScan = 0;
    input.dwFlags = 0; //key-down
    input.time = 0;
    input.dwExtraInfo = IntPtr.Zero;

    input.type1 = 0x01;
    input.wVk1 = 0x90;
    input.wScan1 = 0;
    input.dwFlags1 = 2; //key-up
    input.time1 = 0;
    input.dwExtraInfo1 = IntPtr.Zero;

    IntPtr pI = Marshal.AllocHGlobal(mouseInpSize * 2);
    Marshal.StructureToPtr(input, pI, false);
    int result = SendInput(2, pI, mouseInpSize); //Hardcoded size of the MOUSEINPUT tag !!!

    //if (result == 0 || Marshal.GetLastWin32Error() != 0)
    // Console.WriteLine(Marshal.GetLastWin32Error());
    Marshal.FreeHGlobal(pI);
}
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You can do this via P / Invoke with GetKeyboardState and keybd_event .

The MSDN page for keybd_event shows how to toggle num-lock as well as get state (in C ++).



There are P / Invoke entries on pinvoke.net for keybd_event and GetKeyboardState .

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