controlapp/ControlApp/LockMouse.cs

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace ControlApp;

internal class LockMouse
{
	private delegate nint LowLevelMouseProc(int nCode, nint wParam, nint lParam);

	private const int WH_MOUSE_LL = 14;

	private static LowLevelMouseProc _mouseProc = MouseHookCallback;

	private static nint _mouseHookID = IntPtr.Zero;

	[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
	private static extern nint SetWindowsHookEx(int idHook, LowLevelMouseProc lpfn, nint hMod, uint dwThreadId);

	[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
	[return: MarshalAs(UnmanagedType.Bool)]
	private static extern bool UnhookWindowsHookEx(nint hhk);

	[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
	private static extern nint CallNextHookEx(nint hhk, int nCode, nint wParam, nint lParam);

	[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
	private static extern nint GetModuleHandle(string lpModuleName);

	private static nint SetMouseHook(LowLevelMouseProc proc)
	{
		using Process curProcess = Process.GetCurrentProcess();
		using ProcessModule curModule = curProcess.MainModule;
		return SetWindowsHookEx(14, proc, GetModuleHandle(curModule.ModuleName), 0u);
	}

	private static nint MouseHookCallback(int nCode, nint wParam, nint lParam)
	{
		if (nCode >= 0)
		{
			return 1;
		}
		return CallNextHookEx(_mouseHookID, nCode, wParam, lParam);
	}

	public void Lock()
	{
		_mouseHookID = SetMouseHook(_mouseProc);
	}

	public void Unlock()
	{
		UnhookWindowsHookEx(_mouseHookID);
	}
}