Multithreading in C#

give a try to the BackgroundWorker component: http://emoreau.com/Entries/Articles/2006/12/The-BackgroundWorker-component.aspx

Now, do you need to know when all those threads are complete?  If so there is stuff to add.

I have global variables and references to external web services and essentially reading and writing to/from different xml files and sometimes converting base-64 text to image files while also writing out a log file, and don't necessarily need to know if all threads are complete as I would expect them each to terminate if done at least.  This is essentially a console application that runs behind the scenes on a dedicated workstation that has certificate credentials.

I'm mainly using a Filemaker search application as a front-end from client workstations that sends out the individual file from each client and then waits for a specific answer file to become available before it proceeds.

If all the threads are writing to the same log file then you might want to serialize access to that.  If you have a global variable that stores the name of the log file or something like that just "lock" it when using it.  Look up the lock keyword in online help.
If more than one file will use the same web service connection instance then lock that object as well.

Thanks for suggested code Bearrtloai as I'll give it a try as I hope it's that simple.  Hopefully it does the trick as I don't believe I'll need to lock the log file unless I have fears of there being strange clashes.

Hmmm, I'm not sure what I'm doing wrong here as the ThreadPool.QueueUserWorkItem line doesn't act like it's doing anything upon testing.  Here's a snippet of what I currently have:

           WaitCallback wcbdoRequestFile = new WaitCallback(doRequestFileO);
            while (true)
            {
                string[] files = System.IO.Directory.GetFiles(GlobalVars.REQpath, "*.req", SearchOption.TopDirectoryOnly);
//              acquire all *.req files in folder
                for (int fcnt = 0; fcnt < files.Length; fcnt++)  
                {
                    string rqfile = files[fcnt].Replace(".req", ".re0");
                    System.IO.File.Delete(rqfile);
                    System.IO.File.Copy(files[fcnt], rqfile);
                    System.IO.File.Delete(files[fcnt]);

                    //doRequestFile(rqfile);
                    ThreadPool.QueueUserWorkItem(wcbdoRequestFile, rqfile);
                }
                //Thread.Sleep(1000);
            }
        }

        static void doRequestFileO(object o)
        {
            doRequestFile((string)o);
        }

        static void doRequestFile(string ReqFile)
        {

Edit: nevermind, just seems a bit slower, but now it seems to work.  Strange that I couldn't step through this in my debugging mode.

I'll test this out a bit more, hopefully it works as desired.

So far it works in further tests, shall await when I'm able to get 2 or more users from different workstations to try it out as I now need to post another question on a completely different topic.