/// <summary>
/// Identifies the handler for a device.
/// </summary>
/// <param name="lParam">The handle to a raw input dataset.</param>
/// <param name="rih">Returns the <see cref="RAWINPUTHEADER"/> of the raw input dataset.</param>
/// <returns>The id of the handler.</returns>
public T GetHandlerFromWmInput(IntPtr lParam, out RAWINPUTHEADER rih)
{
rih = RawInput.GetRawInputDataHeader(lParam);
T ret;
if (!front.TryGetValue(rih.hDevice, out ret))
{
return(default(T));
}
return(ret);
}
/// <summary>
/// Enumerate devices and determines the handlers/ids.
/// </summary>
/// <remarks>To avoid conflicks between threads accessing the object, this method
/// should only be call from one thread, maybe in regular intervals (not to short
/// ones; maybe every 10 sec).
/// </remarks>
/// <returns>The number of handled devices.</returns>
public int UpdateDevices()
{
var allDevices = RawInput.EnumerateDevices();
// Remove old entries
back.Clear();
// If we find a change, we will swap front and back.
bool foundNew = false;
// Lock changes to the handlers, while inspecting the devices.
lock (handler)
{
foreach (var device in allDevices)
{
// Query device info.
var deviceInfo = RawInput.GetRawInputDeviceInfo(device.Item1);
// If device was known, test it's old handler first.
if (front.ContainsKey(device.Item1))
{
T id = front[device.Item1];
if (handler.ContainsKey(id) && handler[id](deviceInfo))
{
back.Add(device.Item1, id);
continue;
}
}
// Find the handler
foreach (var idHandler in handler)
{
if (idHandler.Value(deviceInfo))
{
back.Add(device.Item1, idHandler.Key);
foundNew = true;
break;
}
}
}
}
// If something changed, swap the dictionaries.
if (foundNew || back.Count != front.Count)
{
back = Interlocked.Exchange(ref front, back);
}
return(front.Count);
}