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public class MyWpfObject : DispatcherObject
{
    public void DoSomething()       
    {
        VerifyAccess();

        // Do some work
    }

    public void DoSomethingElse()
    {
        if (CheckAccess())
        {
            // Something, only if called 
            // on the right thread
        }
    }
}

// The Work to perform on another thread
ThreadStart start = delegate()
{
    // ...

    // This will throw an exception 
    // (it's on the wrong thread)
    statusText.Text = "From Other Thread";
};

// Create the thread and kick it started!
new Thread(start).Start();

// The Work to perform on another thread
ThreadStart start = delegate()
{
  // ...

  // Sets the Text on a TextBlock Control.
  // This will work as its using the dispatcher
  Dispatcher.Invoke(DispatcherPriority.Normal, 
                    new Action<string>(SetStatus), 
                    "From Other Thread");
};
// Create the thread and kick it started!
new Thread(start).Start();

// The Work to perform on another thread
ThreadStart start = delegate()
{
    // ...

    // This will work as its using the dispatcher
    DispatcherOperation op = Dispatcher.BeginInvoke(
        DispatcherPriority.Normal, 
        new Action<string>(SetStatus), 
        "From Other Thread (Async)");
    
    DispatcherOperationStatus status = op.Status;
    while (status != DispatcherOperationStatus.Completed)
    {
        status = op.Wait(TimeSpan.FromMilliseconds(1000));
        if (status == DispatcherOperationStatus.Aborted)
        {
            // Alert Someone
        }
    }
};

// Create the thread and kick it started!
new Thread(start).Start();

BackgroundWorker _backgroundWorker = new BackgroundWorker();

...

// Set up the Background Worker Events
_backgroundWorker.DoWork += _backgroundWorker_DoWork;
backgroundWorker.RunWorkerCompleted += 
    _backgroundWorker_RunWorkerCompleted;

// Run the Background Worker
_backgroundWorker.RunWorkerAsync(5000);

...

// Worker Method
void _backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
    // Do something
}

// Completed Method
void _backgroundWorker_RunWorkerCompleted(
    object sender, 
    RunWorkerCompletedEventArgs e)
{
    if (e.Cancelled)
    {
        statusText.Text = "Cancelled";
    }
    else if (e.Error != null) 
    {
        statusText.Text = "Exception Thrown";
    }
    else 
    {
        statusText.Text = "Completed";
    }
}

// Create a Timer with a Normal Priority
_timer = new DispatcherTimer();

// Set the Interval to 2 seconds
_timer.Interval = TimeSpan.FromMilliseconds(2000); 

// Set the callback to just show the time ticking away
// NOTE: We are using a control so this has to run on 
// the UI thread
_timer.Tick += new EventHandler(delegate(object s, EventArgs a) 
{ 
    statusText.Text = string.Format(
        "Timer Ticked:  {0}ms", Environment.TickCount); 
});

// Start the timer
_timer.Start();