form using RawInput and Hook to block keys from specific device

HiddenForm.cs

using RawInput_dll;
using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace RFID.Redir.lib
{	
	public partial class HiddenForm : Form
	{
		RawInput rawinput;
		string portName;
		Redirector redirector;
		public List<int> toRemove = new List<int>();

		public event EventHandler NotifyIconDoubleClick;


		public HiddenForm()
		{
			InitializeComponent();
		}
		public HiddenForm(string portName, Redirector redirector) : this()
		{
			this.redirector = redirector;
			this.portName = portName;
		}

		private void HiddenForm_Load(object sender, EventArgs e)
		{
			if (!string.IsNullOrEmpty(portName))
			{
				InitRawInput();
				InstallHook(Handle);
			}
		}

		#region Code of redirection based on RawInput
		[DllImport("HookingRawInputDemoDLL.dll", CallingConvention = CallingConvention.Cdecl)]
		private static extern bool InstallHook(IntPtr hwndParent);

		[DllImport("HookingRawInputDemoDLL.dll")]
		private static extern bool UninstallHook();

		private void InitRawInput()
		{
			rawinput = new RawInput(Handle, false);
			rawinput.AddMessageFilter();
			rawinput.KeyPressed += Rawinput_KeyPressed;
		}

		private void Rawinput_KeyPressed(object sender, RawInputEventArg e)
		{
			const int WM_KEYDOWN = 0x100;

			if (redirector.Redirect(e.KeyPressEvent.DeviceName,
					e.KeyPressEvent.VKey,
					e.KeyPressEvent.Message == WM_KEYDOWN))
			{
				toRemove.Add(e.KeyPressEvent.VKey);
			}
		}

		private void HiddenForm_FormClosing(object sender, FormClosingEventArgs e)
		{
			UninstallHook();
			redirector.Dispose();
		}

		protected override void WndProc(ref Message m)
		{
			const int WM_APP = 0x8000;
			const int WM_HOOK = WM_APP + 1;

			base.WndProc(ref m);

			switch (m.Msg)
			{
				case WM_HOOK:
					for (int i = 0; i < toRemove.Count; i++)
					{
						if (toRemove[i] == m.WParam.ToInt32())
						{
							toRemove.RemoveAt(i);
							m.Result = (IntPtr)1;
							break;
						}
					}
					break;
			}
		}
		#endregion

		private void notifyIcon1_MouseDoubleClick(object sender, MouseEventArgs e)
		{
			NotifyIconDoubleClick?.Invoke(this, e);
		}
	}
}