Threading concept - c#-3.0

Question

Can somebody help me on this:
private Thread workerThread;
private EventWaitHandle waitHandle;
if (workerThread == null)
{
workerThread = new Thread(new ThreadStart(Work));
workerThread.Start();
//workerThread.Join();
}
else if (workerThread.ThreadState == ThreadState.WaitSleepJoin)
{
waitHandle.Set();
}
private void Work()
{
while (true)
{
string filepath = RetrieveFile();
if (filepath != null)
ProcessFile(filepath);
else
// If no files left to process then wait
waitHandle.WaitOne();
}
}
private void ProcessFile(string filepath)
{
XMLCreation myXML = new XMLCreation();
myXML.WriteXml(filepath, XMLFullFilePath);
}
private string RetrieveFile()
{
if (workQueue.Count > 0)
return workQueue.Dequeue();
else
return null;
}
see this is how all this work.
i have a filewatcher event that fires only when new file is being add to that folder, now the problem is its a small part of bigger application and when the file watcher fires there is another process which is accessing that file and i get error like this file is being used by another process. so i have tried to implement through threading but with the above code only some files are being processed, but in the log i can see all the files are being processed. Is it the right way to do it or am i missing something in it
thanks in adv.

Answer 1

You will have to use a mutex to control who is accessing the file and allow only one process at a time to work with that file at the very first time. If you think that there is the possibility that more than one thread will be waiting to work with the same file then you will have to implement a producer-consumer threading system with a queue.
Here is the best documentation about threads you can find in .NET:
http://www.albahari.com/threading/