/////////////////////////////////////////////////////////////////////////////////////////////////
//
// StartEventHandler()
//
// Create the background thread on which the UIA event handler must run.
//
// This function runs on the main UI thread.
//
/////////////////////////////////////////////////////////////////////////////////////////////////
public void StartEventHandler()
{
// This sample doesn't expect to enter here with a background thread already initialized.
if (_threadBackground != null)
{
return;
}
// The main thread will notify the background thread later when it's time to close down.
_autoEventMsg = new AutoResetEvent(false);
// Create the background thread, and wait until it's ready to start working.
_autoEventInit = new AutoResetEvent(false);
ParameterizedThreadStart paramThreadStart = new ParameterizedThreadStart(s_ThreadProc);
_threadBackground = new Thread(paramThreadStart);
_threadBackground.SetApartmentState(ApartmentState.MTA); // The event handler must run on an MTA thread.
_threadBackground.Start(this);
_autoEventInit.WaitOne();
// The background thread is up and running. Have it add the UIA event handler now.
SampleEventMsgData msgData = new SampleEventMsgData();
msgData.msgType = SampleMsgType.msgRegisterEventHandler;
AddMsgToQueue(msgData);
}
/////////////////////////////////////////////////////////////////////////////////////////////////
//
// Uninitialize()
//
// Called on main UI thread to close the background thread down.
//
/////////////////////////////////////////////////////////////////////////////////////////////////
public void Uninitialize()
{
// Tell the background thread to close down.
if (_threadBackground != null)
{
SampleEventMsgData msgData = new SampleEventMsgData();
msgData.msgType = SampleMsgType.msgCloseDown;
AddMsgToQueue(msgData);
}
}
/////////////////////////////////////////////////////////////////////////////////////////////////
//
// Uninitialize()
//
// Called on main UI thread to close the background thread down.
//
/////////////////////////////////////////////////////////////////////////////////////////////////
public void Uninitialize()
{
// Tell the background thread to close down.
if (_threadBackground != null)
{
SampleEventMsgData msgData = new SampleEventMsgData();
msgData.msgType = SampleMsgType.msgCloseDown;
AddMsgToQueue(msgData);
}
// Release all the objects created on startup now.
CleanUp();
}
/////////////////////////////////////////////////////////////////////////////////////////////////
//
// AddMsgToQueue()
//
// Update a list of messages waiting to be processed by the background thread.
//
// Run on the main UI thread.
//
/////////////////////////////////////////////////////////////////////////////////////////////////
private void AddMsgToQueue(SampleEventMsgData msgData)
{
// Request the lock, and block until it is obtained.
Monitor.Enter(_msgQueue);
try
{
// When the lock is obtained, add an element.
_msgQueue.Enqueue(msgData);
}
finally
{
// Ensure that the lock is released.
Monitor.Exit(_msgQueue);
}
_autoEventMsg.Set();
}
