Background Worker Issue

public static void InvokeIfRequired(this DispatcherControl control, Action operation)
{
  if (control.Dispatcher.CheckAccess())
  {
    operation();
  }
  else
  {
    control.Dispatcher.BeginInvoke(DispatcherPriority.Normal, operation);
  }
}

Then, it's simple to do:

Dispatcher.CurrentDispatcher.InvokeIfRequired(()=>{ theButton.Content="Hello"; });

public void Test()
{
    Button theButton = button1 as Button;
 
    if (theButton != null)
    {
        // Checking if this thread has access to the object.
        if (theButton.Dispatcher.CheckAccess())
        {
            // This thread has access so it can update the UI thread.      
            theButton.Content = "Hello";
        }
        else
        {
            // This thread does not have access to the UI thread.
            // Place the update method on the Dispatcher of the UI thread.
            theButton.Dispatcher.BeginInvoke(DispatcherPriority.Normal,
                (Action)(() => { theButton.Content = "Hello"; }));
        }
    }  
}