Yes, that's a horrible hack. That basically guarentees to slow everything down.
I would start a background GUI thread. It will remain running without eating the CPU. You can do this without having another Form with the ApplicationContext class. For example:
///
/// ApplicationContext-based class to be able to create a second message pump
/// Parts lifted from Stephen Toub and http://blogs.msdn.com/toub/archive/2006/05/03/589423.aspx
///
internal class ProgramApplicationContext : ApplicationContext
{
private delegate IntPtr LowLevelKeyboardProc(
int nCode, IntPtr wParam, IntPtr lParam);
private const int WH_KEYBOARD_LL = 13;
private IntPtr hookID;
public ProgramApplicationContext()
{
Form activeForm = System.Windows.Forms.Form.ActiveForm;
// make sure we're informed of the main forms closure
System.Windows.Forms.Form.ActiveForm.FormClosed += new FormClosedEventHandler(ActiveForm_FormClosed);
using (Process curProcess = Process.GetCurrentProcess())
using (ProcessModule curModule = curProcess.MainModule)
{
hookID = SetWindowsHookEx(WH_KEYBOARD_LL, HookCallback,
GetModuleHandle(curModule.ModuleName), 0);
}
}
protected override void Dispose(bool disposing)
{
base.Dispose(disposing);
UnhookWindowsHookEx(hookID);
}
~ProgramApplicationContext()
{
Dispose(false);
}
internal static void StartMonitoringKeystrokes()
{
// create another thread to service another message pump
Thread thread = new Thread(new ThreadStart(ThreadEntry));
thread.IsBackground = false;
thread.Start();
}
private static void ThreadEntry()
{
ProgramApplicationContext ap = new ProgramApplicationContext();
Application.Run(ap);
}
private void ActiveForm_FormClosed(object sender, FormClosedEventArgs e)
{
this.ExitThread();
}
private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
{
Trace.WriteLine(nCode);
return CallNextHookEx(hookID, nCode, wParam, lParam);
}
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetWindowsHookEx(int idHook,
LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool UnhookWindowsHookEx(IntPtr hhk);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
IntPtr wParam, IntPtr lParam);
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr GetModuleHandle(string lpModuleName);
}
Since this class needs to know when the main form is closed, this needs to be run after the main form has been shown. This can be done by handling the Shown event on that form, for example:
private void Form1_Shown(object sender, EventArgs e)
{
ProgramApplicationContext.StartMonitoringKeystrokes();
}